Review NITECORE SRT7i - Smartring, 3000lm

Newly Enlightened
Dec 3, 2012
NITECORE SRT7i was sent to me directly from Nitecore for review.


For technical details and to purchase the torch: … -srt7i.htm

After about 6 years Nitecore updates its great success, the SRT7GT, presenting the new SRT7i of the SRT series which adopts the fourth version of the Smart Selector Ring.
The Nitecore SRT7i, with the fourth generation of the SSR, adopts a rotating ring, positioned at the tail, which allows one-handed control of the Strobe, Turbo, TAC (tactical mode), Lock (Lockout mode) modes and brightness.
This solution makes it really easy to use with one hand by changing the brightness with a simple rotation.

Nitecore SRT7i also adds to these features the double-stage tail buttons which allow, if pressed halfway or fully, two different types of selection. SRT7i is equipped with the "STROBE READY" technology with fast activation of the Strobe.

SRT7i uses a Luminus SFT-70 LED with a maximum output of 3000 lumens and a maximum peak beam intensity of 87,500cd with a maximum throw of 580 meters.

SRT7i is sold with a 5000 mAh lithium battery in 21700 format ("i" series) and is rechargeable via the USB-C port with a maximum autonomy of 800 hours. The SRT7i can also be powered by two CR123A batteries via the adapter (not included in the package).

Nitecore SRT7i has 2 switches, both in the tail, with an IP68 waterproof rating (2 meters submersible) and has impact resistance up to 2 meters.

Note : The stepless brightness adjustment ranges from ULTRALOW (0.1 lumens) to TURBO (3,000 lumens), and the runtime will vary from 800h to 3h 15min due to the different brightness levels.

SRT7i is compatible with already available optional tactical accessories such as, for example, the tail cap with TSL10i signaling LED and the RSW2i remote control, and is particularly recommended for law enforcement, assault operations, self-defense, search and high-risk patrols.


• Dual tail switches enable intuitive operations, specially designed for law enforcement, hunting and tactical applications
• 4th generation of the world's first SSR (Smart Selector Ring) Technology for smoothly and rapidly selecting brightness levels and modes
• Utilizes a Luminus SFT-70 LED with a max output of 3,000 lumens
• Stepless brightness adjustment from 0 – 3,000 lumens
• Stepless adjustment mode, lockout mode and TAC mode available
• An optical system combined with crystal coating and "Precision Digital Optics Technology" (PDOT)
• Max peak beam intensity of 87,500cd and max throw of 580 meters
• Max runtime of 800 hours
• STROBE READY™ Technology to enable a quick access to STROBE Mode
• STROBE Mode uses randomly changing frequencies for stronger dizzying effects
• Equipped with a power indicator
• Intelligent Li-ion battery charging circuit with a USB-C port
• NITECORE 21700i Li-ion battery included (NL2150HPi 5,000mAh)
• Highly efficient constant current circuit provides a stable output
• Anti-impact reverse polarity protection mechanism specially designed for shooting sports
• Incorporated Advanced Temperature Regulation (ATR) module
• Strike bezel uses high strength silicon nitride ceramics to enable excellent glass breaking performance
• Optical lenses with double-sided scratch resistant coating
• Constructed from aero grade aluminum alloy
• HA III military grade hard-anodized finish
• Waterproof and dustproof rating in accordance with IP68 (2 meters submersible)
• Impact resistant to 2 meters
• Tail stand capability


Length: 163mm (6.42") Head Diameter: 40mm (1.57") Tube Diameter: 25.8mm (1.02") Tail Diameter: 31mm (1.22") Weight: 175g (6.17 oz) (Battery Not Included)


Any DOA / defective product can be replaced through a local distributor / dealer

within 15 days of purchase. After that, the defective or malfunctioning product can be repaired free of charge within 60 months from the date of purchase. Beyond 60 months, a limited warranty applies which covers the cost of labor and maintenance, but not the cost of accessories or replacement parts.

Nitecore SRT7i arrives in a dark colored cardboard box with the classic writings that show the main characteristics that distinguish it. Inside my package we find, in addition to the Nitecore SRT7i with the 5000 mAh 21700 lithium battery (NL2150HPi), the holster, the USB-C charging cable, manual and warranty.



The holster in the package is robust, with good thicknesses, with a velcro closure. On the back there is a metal D-ring at the top and in the center a double loop, one of which has a velcro closure. Once inserted, the SRT7i remains stable without strange movements even if a part of the tail remains outside the holster.

Nitecore SRT7i has excellent build quality, there are no strange edges or construction residues. The material with which it is built is in aluminum alloy with anodized finish, black, hard military type.

In the hand it holds well despite the not exactly small at 163mm in length and weight 256g with the battery inserted.
Thanks to the shape of the head and tail, the SRT7i does not roll easily once placed on a table.
The writing on the torch is well made.



On the head of the SRT7i we find a deep projector with SMO reflector with the Luminus SFT-70 LED in the center and optical lenses with anti-scratch coating on both sides. With this LED, Nitecore SRT7i reaches a maximum brightness of 3000 lumens and covers a distance of over 580 meters.


The hardened steel bezel is equipped with 3 high hardness silicon nitride ceramic balls with smooth surface of the balls (to avoid accidental scratches) which allow you to easily break a glass.


On the side, above the head, there is the USB-C format charging socket protected by a metal flap that provides excellent impact resistance. It is easy to lift thanks to the recess under the flap. After connecting the USB-C cable to an external power supply (such as a USB adapter or other USB charging devices) the charging process begins.

During the charging process , the power indicator on the side of the flashlight flashes slowly while when the battery is fully charged, the SRT7i stops the charging process and the power indicator stays on constantly.


According to the manual, the charging time of a 21700i (5,000 mAh) Li-ion battery is approximately 2 hours and 30 minutes (by charging it via a separately supplied 12V/1.5A adapter) in QC (Quick Charge) mode. In my tests it took me about 2h45min to fully recharge the supplied battery.

While charging you can use the SRT7i.

Laterally, on the head, we find the blue light notification LED which indicates, with flashes, the battery charge status and, with a normal or fast flash, when the battery is running low.

Power indication

When the light is on, the power indicator will display the remaining battery power.

1 . Steady light indicates that the power is greater than or equal to 50%.
2 . Slow flashing indicates power is less than 50%.
3 . Fast flashing indicates power is less than 10%.


The central body of the Nitecore SRT7i has a rhomboid-shaped non-slip knurling and two spaces that offer the possibility of inserting accessories such as the Tactical Ring Pro NTR10.
The threads on the torch body (to screw the cap) arrive well greased. They are anodized and therefore, by partially unscrewing the tail cap, they allow the mechanical locking of the torch. There is an O-ring to seal against water and dust. Nitecore SRT7i is IP68 certified (2 meters submersible).


At the two poles, for contact with the battery, we find a system designed in particular for shooting sports with plated rings and springs at the head while a button plated contact system at the tail. SRT7i has shockproof reverse polarity protection mechanism.


The battery supplied to operate the SRT7i is a Nitecore 21700 protected (NL2150HPi 5.000 mAh 15A) of the "i" series.
The NL2150HPi is a proprietary 21700 rechargeable Li-ion battery with a dual-way output with positive and negative polarity on both ends. It allows for a highly efficient 15A output while minimizing power loss due to internal resistance. It has high temperature resistance and built-in PTC to inhibit high current peaks. Automatically protects against overload, over discharge and short circuit.

The only unscrewable part of the SRT7i is the tail cap. On the tail cap we find the fourth generation Smart Selector Ring (SSR).

The fourth generation intelligent selector ring and tactical dual buttons on the tail are applicable for one-handed control of STROBE mode, TURBO level, TAC mode, Lockout mode and levels of brightness.


On the tail cap there are two dual-stage electronic switches; Power Button and MODE Button.


The metal power switch, Power Button, round in shape, is raised compared to the larger MODE button and equipped with a knurling. The Mode Button (dual stage) has a double function if pressed halfway or fully. Furthermore, the MODE button is slightly raised and not flush as, for example, on the P20i, making its activation easier and faster.

The U-shaped tail prevents accidental activation of the switch and allows the SRT7i has tail stand capabily. The supplied lanyard can be inserted into the two holes on the cap.


We see the Nitecore SRT7i near to other flashlights.

From left: Battery Nitecore NL2150HPi, Nitecore P20i, , Nitecore SRT7i, Acebeam T27 e Cyansky K3 v2.



Nitecore SRT7i has two switches in the queue and, through the rotating ring, the possibility of continuous brightness variation from 0.1 lumens of Ultralow to 3000 lumens of Turbo, in addition to the special STROBE mode.

o UltraLow: 0.1 lumens / 800 ore
o Turbo: 3,000 lumens / 3h15 minuti / 580 metri
o Strobe: 3,000 lumens

For the use of the Nitecore SRT7i refer to the online manual:



The beam of the Nitecore SRT7i is uniform with a pleasant tint and no visible artifacts. With the lighting test on the wall, a large and bright white spot is noticed, while the ring that surrounds it is tending towards yellow.

In the image below we see the wall test of the beam of the Nitecore SRT7i together with the Nitecore P20i and the CYANSKY K3v2.


Nitecore SRT7i given its characteristics, having a deep projector, it is a tactical flashlight with a deep beam with long-range illumination particularly suitable for outdoor use such as for research and law enforcement . I can't see any significant PWM in any mode by eye. The start of the spill from the walk is over two meters.


The CCT (color temperature) and Ra (color rendering) values taken with the OPPLE Light Master Pro, at a distance of two meters from the sensor, vary according to the selected light level.
In my test the CCT color temperature values vary from about 5800 of the low value up to the value of 6562 of the 3000 lumens Turbo level.
The color rendering Ra ranges from a value of 66.9 to a value of 71 with the maximum brightness of the Turbo level.
The calculated Duv with the brightest level is 0.0021.


The peak values in candela (cd) taken with the Luxmeter at 5 meters reflect those declared by the parent company. In Turbo the recorded value was 90,000 candela.


With a FLIR ** thermal imaging camera ** I detected how the heat is distributed on the flashlight in TURBO mode at 3000 lumens after 2min and 10min from switching on.


The Runtime were done in a closed environment with a temperature of about 20°C using the supplied fully charged Nitecore 21700 5000 mAh battery.

I would like to point out that the values expressed by the graphs must be taken, above all, as a reference because they are made with means and environmental conditions different from those used in the laboratory.

Note: Nitecore SRT7i, with the ATR module, adjusts its output power by adapting to the surrounding environment, maintaining optimal performance.

The first test was done by putting the Nitecore SRT7i in Turbo (3000 lumens) with the supplied battery fully charged. After switching on, there is a constant descent of the luminous curve until it settles down, after almost 3 minutes, at about one third of the initial luminosity. This trend is maintained for approximately two hours after which the light output is progressively reduced in small steps. When the battery is low, the notification LED flashes quickly to warn the user.
The same test was done by placing a small fan near the Nitecore SRT7i. From the graph you can see the difference of the two curves by cooling the SRT7i.
The last test was done by setting the brightness, using the rotating ring, to about a third of the highest value (Turbo) measured in cd. After an initial climb the performance roughly mirrors that obtained in turbo after the initial descent.



VIDEO Review

Nitecore SRT7i, Unboxing and Use


After about 6 years Nitecore updates the previous SRT7GT with a new revised model with improved performance. Nitecore SRT7i is a well built tactical flashlight that has the great advantage, through the fourth generation rotating ring (SSR), of being able to vary the degree of brightness on different levels, ranging from 0.1 up to 3000 lumens. In addition, the two dual-stage tail buttons provide comfortable control in tactical operations.
Nitecore SRT7i has a powerful beam and good autonomy. The many positive aspects of the SRT7i make it an interesting and definitely recommended product for law enforcement, hunting and tactical applications.
Thanks for reading the review.