maybe this will help. i've been upgrading my own list as i gather new info....
Arc LS Series - Models and Variations
The Arc Company of Tempe, Arizona was started in May of 2001 by Peter Gransee.
First Run Model
This was the first flashlight on the market using a Luxeon Star Low Dome LED.
version 0.9 - First shipped in December of 2001. Voltage regulated. 3 battery packs (1x123, 1xAA, 2xAA)
version 1.0 - First shipped in February of 2002. Switched to NX05 optics
Hybrids
These were hybrids of the first and second (Rev2) revision levels of technologies.
400 Hybrid – Bridge between version 1 and version 2, it had the original housing of first version and the new circuit of second version, set for 330mA (mistakenly reported as 400mA)
500 Hybrid – Same as 400 but circuit was set for ~400mA (mistakenly reported as 500mA)
LS1
This was the first total Rev2. $120 Retail
version 2.0 - New current regulated circuit design, thermal circuit breaker, higher output, gold contacts, waterproof, slimmer design, Lexan protected optics, new one piece head design.
version 2.1 - Flex washer (fixes flex failure)
LS2
First flashlight on the market to use the Luxeon Star High Dome LED. Rev2 technology.
LS3
First flashlight on the market to use the 5 Watt Luxeon Star driven at 2 Watts. Rev2 technology. 2x123 battery. Waterproof. Shipped to Arc Fans in January of 2003. Discontinued in favor of longer life emitters and better technology to be used in the LS5.
LSL ( aka: LSL-S )
Renamed LS1 with v2.1 improvements. Low Dome LED with M-N Flux and 3-4 Tint. $120 Retail
In late 2002, the 1x123 battery pack was changed from the twist design to the TSP (Tail Switch Pack) design on all models. Dimensions on all LSL & LSH variations are 3.2" long x .95" diameter and 2.2 ounces.
LSH ( aka: LSH-S )
Renamed LS2 with v2.1 improvements. High Dome LED with M-N Flux and 3-4 Tint for a more focused and whiter beam. $130 Retail
LSL-P
Premium version of LSL with P-Q Flux and 3-4 Tint for a brighter beam. $150 Retail
LSH-P
Premium version of LSH with P-Q Flux and 3-4 Tint for a brighter beam. $160 Retail
LS4 (expected March 2004)
Has "Boost" function which provides 5-30 seconds of overdrive brightness. New tail switch design provides lower profile, fewer parts and more reliability. Removable pocket clip. Numerous brightness levels. Automatic Tint control. New reflector design. 2.8" in length with 1" in diameter head. 2.5 ounces with 123 battery. Will be available in 2 grades, Standard ($150 Retail) and Premium ($180 Retail). Premium uses a LED hand selected for brighter output.
LS5 (expected mid-2004)
Will have a 5 Watt Luxeon Star driven at 3 Watts using two 123 batteries. Enlarged housing and optics. It will have many of the same features as the LS4 but having a more powerful beam.
