The Microstream offers good illumination capability in an unobtrusive package no larger than a ballpoint pen, which means it can always be on your person when you need a light source. Features include a 1/2 watt LED bulb that produces 28 lumens of clear white light, an unbreakable polycarbonate lens, aircraft aluminum body, O-ring seal, tailcap activation switch, pocket clip, keyring and lanyard. Requires 1 AAA battery (included). Lifetime factory warranty. Length: 3.5". Weight: 1.04 oz. Runtime: 1.5 hrs.Specifications and Features:28 lumen output1.5 hour runtimeInternal polymer body liner and shockproof switch housingRubber push button tail cap switchO-ring sealedPolycarbonate lensCorrosion and water resistant constructionPocket clipKey ring and lanyard includedUses one AAA alkaline battery, includedWeighs 1.04 oz with battery3.5" long