Warning: even more pic heavy than usual.
The RRT-21 (1x18650, 2xCR123A/RCR) and RRT-15 (3xCR123A/2x18500) are the two latest members of the recently re-designed JetBeam Rapid Response Tactical series (see my original RRT-2 review here). Both lights feature a continuously-variable magnetic control ring. Let's see how they compare to the competition, shall we?
Common Manufacturer's Specifications:
- LED: CREE XM-L T6
- Rapid Response Control Ring for infinite adjustability
- Reflector: Aluminum Reflector
- Lens: Toughened ultra-clear mineral glass with anti-reflective coating
- Material: Aircraft Grade Aluminum Alloy
- Finish: Military Grade Type III Hard-anodized
- Rated IPX-8 Waterproof
- Impact Resistance in accordance with MIL-STD-810F
- Switch: Tactical Forward Click Switch
- Stainless steel retaining ring on the bezel protects the head from drops and impacts.
- Innovative new hybrid reflector specially designed for CREE LED offers an improved beam with a superior throw
- Newly designed high efficiency broad voltage drive circuit
- Floating positive end, designed for better contact
- Candle Stand Tailcap
RRT-21 Specific Specs:
- Maximum Output: 480 lumens with a throw of 508.5 Feet (155m)
- Battery: 2xCR123A, 2xRCR123 or 1x18650 Li-ion
- Dimensions: Head Diameter: 1.34" (34mm), Tube Diameter .91" (23mm), Total Length 5.63" (143mm)
- Weight: 4.83oz (137g)
- MSRP: ~$105
RRT-15 Specific Specs:
- Maximum Output: 480 lumens with a throw of 748 Feet (228m)
- Battery: 3xCR123
- Dimensions: Head Diameter: 1.89" (48mm), Tube Diameter: 1" (25.4mm), Total Length 7.4" (188mm)
- Weight: 7.5oz (200g)
- MSRP: ~$120
The lights come in standard JetBeam packaging – hard cardboard box with magnetic closing flap, and cut-out foam to secure the light. Inside you will find the light, wrist lanyard, spare o-rings, tailcap button cover, and manual. There is also a removable pocket clip installed on the light.
From left to right: JetBeam Jet-III M; Nitecore IFE2; JetBeam RRT-21, RRT-15; Olight M31; Surefire UB3T
All dimensions are given with no batteries installed:
JetBeam RRT-21: Weight: 137.3g, Length 143.3mm, Width (bezel) 33.8mm
Sunwayman V20C: Weight: 117.4g, Length 133.0mm, Width (bezel) 32.2mm
Nitecore IFE2: Weight: 65.1g, Length 127.1mm, Width (bezel) 23.6mm
JetBeam RRT-15: Weight: 203.2g, Length 187mm, Width (bezel): 48.7mm
Surefire UB3T: Weight: 311.1g, Length 229mm, Width (bezel): 63.1 mm
Olight M31 (no extender): Weight: 258.1g, Length 209mm, Width (bezel): 62.3mm
Lumintop TD-15X (no extender): Weight 150.3g, Length 147.3mm, Width (bezel) 37.8mm
The overall weight and dimensions of the RRT lights are reasonable for their classes. The RRT-15 is smaller than most dedicated 3xCR123A lights.
The overall build is virtually the same, so I'll just show one set of pics below:
Build is good quality for both lights. Anodizing is an excellent dark gray, very smooth and consistent. Labels are clear and bright white.
Overall build is reminiscent of some of the recent Nitecore lights, as well as the JetBeam B-series budget lights (note that both brands are now owned by Sysmax). There is knurling on the magnetic control rings of each light, and the RRT-15 has additional knurling on the body (although it isn't very aggressive in either location). With the removable clip attached, I would say grip is good on both lights.
The clip is actually fairly basic, although it fits on firmly enough – a standard removable clip-on style, as found on the B-series lights.
There are a fair number of screw threads, anodized for tailcap lock-out.
There is a raised post on the positive contact plate in the head, so higher capacity flat-top cells can be used.
Both lights can tailstand, but I find them a little wobbly.
There are clear detents on the magnetic control ring for Strobe, Off, and Max. There are no labels indicating these modes, though.
Which brings me to a more detailed examination of the build and user interface, starting with a video overview:
Video was recorded in 480p, but YouTube defaults to 360p. Once the video is running, you can click on the 360p icon in the lower right-hand corner, and select the higher 480p option, or even run full-screen.
The RRT-21 and RRT-15 have the same interface. Both lights have a forward tailcap clicky - press and release for momentary on, click for locked on.
Mode switching is controlled by the magnetic control ring in the head. The lights use an identical continuously-variable interface – you control the output level by twisting the ring. You can select your desired mode while the light is off (i.e., relative position of the ring).
The ring traverses a little under 1/2 of the circumference of the light, which I personally like. When holding the light in front of you, turning the ring clockwise (i.e. to the right) increases the output level. There is a clear and firm detent just below the minimum output, which is a standby "Off" mode. A little further pass standby is another detent for the Strobe mode.
The control ring has good grip thanks to the knurling, but there are no labels indicating relative output modes.
The RRT-21 and RRT-15 do not use what is commonly referred to as a "visually-linear" or logarithmic ramp, unfortunately. I find this rather surprising, given the Nitecore IFE2 has a well-implemented "visually-linear" ramp.
To explain, "visually-linear" is usually taken to mean a logarithmic ramp as opposed to an actual circuit-linear ramp of outputs. The reason for this is that we perceive brightness in a non-linear way (actually, not just brightness - most of our sensory perceptions are non-linear). This is part of why twice the lumens doesn't appear twice as bright to us - lumens are an objective (linear) measure of output, and our subjective perceptions are not linear. A logarithmic adjustment has long been used to try to adjust for our relative visual perceptions (e.g. the stops of camera are logarithmic).
However a logarithmic adjustment is not entirely accurate – it is just a rough approximation of how our eyes and brain adapt to varying output levels (and one based on Victorian-era science at that). More extensive scientific research over the last several decades has revealed distinct power relationships that better correlate to our various relative sensory perceptions. For perceived brightness, the currently accepted linearization method is actually a cube root of output. For a full discussion of this - including detailed graphs and primary literature references - please see post #3 in my Sunwayman V10A review.
To put that in practical context, here is what the RRT-21 and RRT-15 look like in my lightbox, compared to two other lights of the same class also use "visually-linear" (i.e., logarithmic) ramping control rings.
The V20C has a similar pattern to the Nitecore IFE2, which clearly differs from the JetBeam RRT-21/15. Looking at the above graphs, it may appear to you that there is something wrong with the V20C and IFE2 – nothing happens over the early portion of the ring. In fact, the light is adjusting the output – it is just that it does so in a non-linear fashion, starting at really low levels and slowly ramping up.
A much better way to depict how we perceive this change is to plot the lightbox output on a cube-root scale, the Stevens’ power law relationship:
This is what you can expect to see when you handle the lights (note both RRT lights have identical outputs and ramp patterns). Thus, the RRT-21/15 spend the largest portion of their ramp in the near maximal range of perceived output levels. There is a relatively narrow range of the ring that controls the perceived low levels. The lights do not go as low as some other continuously-variable lights (see my Summary Tables later in this review for some lumen estimates).
Personally, I prefer the nearly "visual-linear" ramp of the V20C and IFE2, as they provide a better subjective experience – plus greater control over a wider dynamic range (thanks to the lower Lo modes).
I have measured the battery current draw at the standby "Off" detent of both lights. For the RRT-21, I get 19.2mA on both 1x18650 and 2xCR123A, which for a standard 2400mAh 18650 and 1500mAh CR123A, would translate into 5.2 days and 3.3 days respectively (before fully-charged cells would be completely drained). For the RRT-15, I measured 19.1mA on 2x18500 and 3xCR123A, giving you a comparable 3.3 days.
These are significant current drains, so I recommend you always fully lock-out the light by either clicking the tailcap off, or unscrewing a quarter turn.
To put these numbers into perspective, these current draws on standby are about twice as high as the Nitecore IFE2, and 270 times higher than the Sunwayman V20C.
Note that this also means you can't expect more than a couple of days of runtime at the lowest outputs (i.e., by definition, current draw when on can't be less than the standby current). This is common with most lights with continuously-variable control rings – the circuit overhead is considerable, limiting runtimes at the lowest levels.
Strobe was measured at a consistent "tactical" 12.7 Hz on both RRT lights.
PWM is a bit harder to assess. Subjectively, I didn't notice any flicker, and my oscilloscope didn't detect standard "square-wave" PWM (i.e. a constant frequency, where the duty cycle changes with output). Instead, a variety of high-frequency noise was observed, whose frequency sometimes varied with the output setting.
Note that none of this was visible to the eye, but here are the oscilloscope traces if you are interested:
Max output on the RRT-21 switched between a 15 kHz and 22 kHz signal, with a regular pattern.
RRT-21 Relatively Hi:
A different secondary pattern was obtained as I lowered the output, although still with a 22 kHz core harmonic.
By the lower levels, the frequency had shifted to a more consistent 15 kHz on the RRT-21.
On the RRT-15, a similar pattern was observed, though varying from 9 to 11 lHz.
Note that none of this was visible by eye – the noise is of sufficiently high frequency so as to be invisible. For all intents and purposes, you shouldn't notice anything but consistently smooth output.
Both lights use Cree XM-L emitters (well centered on my samples, with a surrounding mask). The RRT-21 reflector has a very light level of stippling (i.e., those faint concentric rings you can see above), but is otherwise smooth. The RRT-15 has medium-to-heavy orange peel effect (i.e., a textured reflector). I would expect a fairly typical beam pattern for the RRT-21, for a light of this size. The RRT-15 should have decent throw, given the reflector size, but likely not as great as those lights with a smooth reflector.
And now the white-wall beamshots. All lights are on max output, on 1x18650 or 2x18500/3xCR123A (depending on the class of light). Lights are about ~0.75 meter from a white wall (with the camera ~1.25 meters back from the wall). Automatic white balance on the camera, to minimize tint differences.
Beam profile of the RRT-21 is remarkably similar to the Sunwayman V20C. An overall balanced beam for a XM-L light.
As expected, the RRT-15 has reasonably good throw. However, it is not as focused for throw as some others in this class with smooth reflectors/optics. Max output also seems lower than typical (scroll down to my Summary Tables for a detailed comparison).
UPDATE Nov 15, 2011: And now for the outdoor shots. These beamshots were done in the style of my earlier 100-yard round-up review. Please see that thread for a discussion of the topography (i.e. the road dips in the distance, to better show you the corona in the mid-ground).
Sorry, the PA40 should say 4x, not 8x.
All my output numbers are relative for my home-made light box setup, a la Quickbeam's flashlightreviews.com method. You can directly compare all my relative output values from different reviews - i.e. an output value of "10" in one graph is the same as "10" in another. All runtimes are done under a cooling fan, except for any extended run Lo/Min modes (i.e. >12 hours) which are done without cooling.
I have recently devised a method for converting my lightbox relative output values (ROV) to estimated Lumens. See my How to convert Selfbuilt's Lighbox values to Lumens thread for more info.
Throw/Output Summary Chart:
Effective November 2010, I have revised my summary tables to match with the current ANSI FL-1 standard for flashlight testing. Please see http://www.sliderule.ca/FL1.htm for a description of the terms used in these tables.
I am happy to report that the published output and throw specs for these lights seem very accurate and consistent to what I observed.
Max and min output is virtually identical between the RRT-21 and RRT-15 (as you could also tell from the ramping charts). Overall max output is around middle-of-the-pack for a 2xCR123A/1x18650 XM-L light.
As expected from the beamshots, overall output and throw of the RRT-21 are very similar to the V20C. Again, a good balanced beam.
I’ve put two sets of Min values in the tables for the recent ramping lights; the first number is the minimum output when ramping down the light (before hitting Off), the second number (in brackets) is the lowest output when ramping up from Off. Many of these lights come on at a slightly higher output than they can ramp down to.
The RRT-15 has reasonable throw for the size, but absolute max output and throw are low for this class of 3xCR123A/2x18500 lights.
RRT-21 runtimes are very good - about what you would typically expect to see for a good-quality, defined-level 2xCR123A/1x18650 XM-L-based light. Considering the RRT-21 is continuously-variable (with a much greater range of outputs), that is very impressive.
The RRT-15 also has a typical runtime profile for a good 3xCR123A light. I don't have a lot of data on 2x18500, but below I will compare the RRT-15 on 2x18500 to other lights on 2x18650 and 3xRCR:
Again, the RRT-15 is surprisingly efficient on 2x18500 (1500mAh) – matched for output, runtimes are typically comparable to 2x18650 (2200mAh), on most XM-L-based lights. The RRT-15 on 2x18500 definitely outperforms 3xRCR-equipped competitor lights.
Magnetic control ring ramp is not "visually-linear", as some competing lights are.
Lights do not go to as low output levels as some competing lights (but ~3 lumens is still respectable, and lower than most lights with defined levels).
Standby current is relatively high, and will drain a fully charged battery within a few of days. Recommend you all store the light either clicked-off, or locked out at the tailcap.
I experienced a switch failure on my RRT-21 sample shortly after testing began (I was able to complete testing using the RRT-15 tailcap on both lights). JetBeam is sending me a replacement switch.
The JetBeam RRT-15 and RRT-21 are solid lights, well-made with a number of good design features.
They do differ somewhat in appearance from the earlier high-end JetBeam lights. While those lights were also high-quality, they were often a little rough-around-the-edges (i.e. they felt more like custom lights at times). These new specimens are very "polished" by comparison, but may not be as heavily distinguished from the B-series of JetBeam lights as some would like.
Of course, the JetBeam B-series lights are remarkably good quality for the price. But I note that the threading diameter and thickness here seems to be same as the B-series lights (e.g. the BC40 tailcap screws onto and activates these lights, although isn't as deep overall). Normally, I see square-cut threads on higher-end lights like these. Similarly, the reflector in the RRT-15 has exactly the same appearance and dimensions as my BC40 (which may explain the odd choice of a more textured reflector on the "throwier" RRT light). Even the (fairly basic) pocket clips here seem to be virtually the same design as the BA/BC series pocket lights.
That said, I certainly like the excellent quality of the natural-finish anodizing on these RRT lights (a very Sunwayman-like dark gray, as opposed to the earlier sandy-gray colored JetBeams). I also like the knurling on the control ring, which makes it easy to access. And I personally like the length of the traverse (i.e. around half the circumference of the light), although I know some like it shorter.
User interface is good, with clear and sharp detents (and with SOS "hidden" below the standby-Off detent). Unfortunately, the control ring ramp is not "visually-linear", so that means you will spend most of that ring traverse choosing between what appears to be mainly near-max levels.
I am happy to report that JetBeam seems to be very accurate in their ANSI FL-1 output, throw and runtime specs for these lights. I also like the lack of visible PWM.
Overall efficiency is excellent on both lights – remarkably so, given their continuously-variable interface (i.e. they match or exceed a number of defined-level lights). I was particularly impressed with the performance of the RRT-15 on 2x18500 cells – outstanding runtime for a continuously-variable light, given the 1500mAh rated capacity of those cells (i.e. matches most defined-level lights on 2200mAh 18650).
The new RRT lights by JetBeam certainly have a lot going for them. If JetBeam were to integrate the comparable "visually-linear" ramp of their sister-company Nitecore (i.e. IFE2), I think the interface would be just about perfect. But output/runtime performance is already excellent on these lights as is, and build quality is solid.
RRT-15 and RRT-21 provided by JetBeam for review.