The Powertac E1 produces an amazing 350 lumens with four levels of brightness plus strobe. This compact keychain light can also be used as a great everyday carry pocket light. Its compact size and lightweight design make it the top choice in its category. This incredibly practical accessory is powered by a single CR123A battery.Features: Slightly twist the head to activate firefly mode (3.5 Lumens) then tighten further for maximum output (350 Lumens) Memory function to stay at any one of the 5 modes Regulated Current for smooth, consistent, strong current Aircraft-quality aluminum body structure Premium type III hard anodized anti-abrasive finish Tempered, double-coated ultra-clear glass lens Smooth reflector for maximum beam and light output Can stand on tail to serve as candle Waterproof to IPX-8 standard One-handed operation Reverse polarity protection Included accessories: 1 Key ring Specifications: LED: CREE XM-L Runs on: 1x CR123A (Battery not included) Output mode/Runtime: High: 350 lumens / 0.66h Mid: 150 lumens / 1.6h Low: 61 lumens / 3.5h Firefly: 3.5 lumens / 80h Strobe: 350 lumens / 1.5h Dimensions: Length: 2.75" 70(mm) Diameter: .86" 22(mm) Weight: 1.23 oz 35(g) (excluding batteries)