Main Features and Specifications

LED: Cree XHP35 Neutral White (Nominal CCT 4500K)
User Selectable Levels: 3 main levels (High, Medium and Low). Each main level can be programmed to one of its two sub-levels. The second sub-level of the each main levels can be further programmed to different brightness levels.
Light Output (runtimes)
High:         H1 1092 Lm (PID, approx 2.2 hr)   or    H2  563 Lm (PID, approx 2.8 hrs) / 303 Lm (4.3 hrs) /135 Lm (12 hrs)
Medium:    M1 59 Lm (33 hrs)    or    M2   27 Lm (73 hrs) / 10 Lm (8 days)
Low:         L1   3.2 Lm (18 days)   or    L2   0.36 Lm (2.8 months) / 0.05 Lm (5.1 months) / 0.01 Lm (7.1 months)
Beacon Strobe Mode: 0.2Hz Beacon at Low / 0.2Hz Beacon at H1 / 4Hz Strobe at H1 / 19Hz Strobe at H1
 
Light output are ANSI out the front (OTF) values. Runtimes tested (and parasitic drain estimated) using ZL634 batteries. Runtimes of the two PID controlled levels (1126Lm and 580Lm) vary greatly with ambient temperature and air circulation.
Operating Voltage Range: 2.7V - 6.0V
Battery: One 18650 size (up to 69mm long) 3.6V-4.35V li-ion rechargeable. Batteries are not included in the package.
Parasitic Drain: Negligible (much less than the self discharging of a battery)
Beam Type
Floody beam from frosted lens, with 90 degree beam spread
Dimensions
Head Diameter: 0.95 inch (24.2 mm)
Length:    3.85 inch (97.8 mm)
Weight
1.4 oz (39 gram) 
3.0 oz (84.6 gram) with ZL634 battery
4.4 oz (124.6 gram) with ZL634 battery and headband
Features
PID thermal regulated outputs (1092Lm and 563Lm)
Battery capacity indicator (LED flashes 1-4 times, 4 short clicks to start)
Automatic stepping down from High to Medium, and from Medium to Low when battery capacity is low
Builtin over-discharging protection (2.7V cutoff)
Durable electronic soft-touch switch
Smart user interface provides fast and easy access to all brightness levels and beacon-strobes.
Precision machined unibody casing from premium grade  aluminum bar stocks
Proprietary heat sinking design bonds the LED board directly to the unibody aluminum casing
Durable natural hard anodized finish (Type III Class I)
Sealed and potted LED driver circuitry
Battery reverse polarity protection
Tempered optical grade glass
Waterproof to IPX7 (2 meters, 30 minutes)
Operations

This light has 3 main levels (High, Medium, and Low) and a beacon-strobe mode. Each main level can be programmed to one of its two sub-levels. The second sub-level of each main levels can be further programmed to different brightness levels.

Basic Operation
One short-click turns on the light to High or turns off the light.
Two short-click turns on the light to Medium.
Three short-click turns on the light to the beacon-strobe mode.
Press and hold (for over 0.6 seconds) turns on the light to Low and then Medium and High. Release at the desired level.
Advanced Operation and Configuration
Press and hold to cycle from Low, Medium and High, release at the desired level to set. When press and hold, the light always cycle from Low to High regardless which level you are currently in.
Double click to toggle and select between the two sub-levels for that main level. Sub-level selections for the 3 main levels are memorized after the light is turned off and through battery changes.
The second sub-level (H2, M2 and L2) of each main levels can be further programmed to different brightness levels. At a main level, double-click 6 times to start configuration. On subsequent double-clicks the light will cycle through different brightness levels. Short click to turn off the light when finishing configurations. The selections for the second sub-levels are memorized after the light is turned off and through battery changes.
This light uses the main LED (flashing 1 to 4 times) to indicate the estimated remaining capacity of the battery. To start the battery indicator, (from Off) short-click 4 times without pause.
Beacon-strobe mode can be accessed from 3 short-clicks when the light is Off. Once in the beacon-strobe mode, you can double-click to cycle through different types of beacons and strobes. Beacon-strobe settings are memorized when the light is turned off and through battery changes.
 

Accessories in the package

Two o-rings
Headband with removable top strap, and a black silicone holder