Cree XHP50.2 Neutral White LED, Nominal CCT: 4000K, Typical CRI: 93-95, Tint deviation: 3-step. 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. Operating Voltage Range: 2.7V - 6.0V. Battery: One 18650 size (up to 69 mm) 3.6-4.35V 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 ZL635 battery, 4.4 oz (124.6 gram) with ZL635 battery and headband. Features PID thermal regulated outputs (three highest output levels). Builtin battery protections with continuously monitored temperature, current, and voltage, plus a (2.7V) low voltage cutoff. 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. Durable electronic soft-touch switch. Sealed and potted LED driver circuitry. Tempered optical grade glass. Orange peel textured reflector. Battery reverse polarity protection.