Automatically lights itself and activates when in the water and begins strobing. Bright light in all directions (360� visibility). UV resistant polycarbonate case. Bracket is included and maintains same hole pattern as SM-2 for easy retrofit High intensity LED strobe. Floats upright in all conditions. Minimum 40 hours continuous operating life. Dimensions: 9.9″ length x 2.2″ diameter. Drop tested 249 ft. (76 m) into water. Operates on (2) “AA” Lithium batteries (Not included). USCG/MED/SOLAS Approved.