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