LED: Cree XM-L2 Cool White (Norminal CCT 6300K). 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 each main level can be further programmed to different brightness levels or strobes. Light Output – High: H1 278 Lm (0.9 hrs) or H2 171 Lm (1.9 hrs) / 107 Lm (3.3 hrs), Medium: M1 53 Lm (7.5 hrs) or M2 27 Lm (12 hrs) / 13 Lm (27 hrs), Low: L1 2.9 Lm (4 days) or L2 0.36 Lm (3 weeks) / 0.06 Lm (2 months) / 0.01 Lm (3 months), Beacon Strobe Mode: 4Hz Strobe at H1 / 19Hz Strobe at H1. Light output are ANSI out the front (OTF) values. Runtime tests are done using Sanyo 2000mAh Eneloop AA batteries. Operating Voltage Range: 0.7V – 2.5V. Battery: One 1.5V AA (NiMH, lithium or alkaline; not included). 14500 Li-ion batteries are not supported. Flood beam with 120 degree beam spread. Dimensions – Diameter: 0.84 inch (21.3 mm), Length: 2.76 inch (70.1 mm). Weight – 1oz (29 gram), 2oz (55 gram) with an Eneloop AA, 2.8 oz (78 gram) with an Eneloop AA and headband. Features – Electronic soft-touch switch, with a 200,000 cycle operating life, Precision machined unibody casing from premium grade Alcoa aluminum bar stock, Proprietary heat sinking design bonds the LED board directly to the unibody aluminum casing, providing unblocked thermal paths to over 92% of the surface area. Durable natural hard anodized finish (Type III Class I). Tempered optical grade glass. Waterproof to IPX8 (2 meters, 30 minutes). Accessories in the package: Pocket clip, One black silicone holder with headband, Two o-rings.