The Pelican™ tactical flashlight uses 1 AA battery, or upgrade to 2 CR123 batteries to bring you up to 1018 lumens of bright LED light. It has high, medium, low and strobe beam light output modes, 4 programmable modes, 5 selectable programs and a full-time battery indicator, making this the most efficient tactical light you will ever own. Its push button / momentary button makes it a convenient light source that will run up to 33 hours on the low beam setting with 2 CR123 batterines. The Type III Anodized aluminum body, IPX8 (1m) rated lens and carbon steel clip make it durable and convenient to carry. Includes 1 AA battery and Pelican's unconditional lifetime guarantee of excellence.