The UST See-Me 1.0 Strobe personal locator light strobes 60 times per minute for maximum visibility in all directions. On the trail or on the water, it's the perfect companion for your pack or PFD ensuring you can be located quickly in an emergency situation.FeaturesLifetime LED bulb never needs to be replacedProvides 28 lumens of light; runs for 44 continuous hours onWaterproof IPX7Visible 2.7 miles (4.3 km) on a dark, clear night which exceeding USCG requirements of 1 nautical mile (1.9 km) visibilityU. S. Coast Guard-approvedEasy twist On/OffLanyard cord and hook-and-loop strap includedBATTERIES: 2 AAA alkaline batteries (not included)