The UST See-Me™ 2.0 Strobe personal locator light strobes 60 times per minute providing 45 lumens of light for maximum visibility in all directions. This U.S. Coast Guard approved LED strobe automatically activates when it comes in contact with water.45 LumensUp to 120 hours run timeWaterproof IPX7Activates when submerged in water; will not automatically activate with rain, sea spray or high humidityCan be manually activated with easy twist On/OffVisible 3.1 miles (5.0 km) on a dark, clear night which exceeds USCG requirements of 1 nautical mile (1.9 km) visibilityClip, lanyard cord and hook-and-loop strap includedRequires 2 x AA alkaline batteries (not included)