Unique features include 66 channel GPS (3 metre accuracy) The GPS location is updated and transmitted every 5 minutes, Transmits 121.5MHz signal for rapid homing, Non hazmat battery, safe for air transport, Self buoyant without external floation. 10 year battery, 10 year warranty, 20 year life. Dimensions, 88mm high, 65mm wide, 32mm deep, weight 140gms.