The SpeedPuck is for the minimalist sailor who wants a reliable easy to use instrumentation which provides you with the essitial information for performance sailing, speed and heading. The SpeedPuck combines a high-accuracy GPS speedometer, compass and bar graph wind shift indicator in a compact, durable package. It is designed to be mounted on a dinghy or handheld when hiking on a sportboat. The SpeedPuck improves your sailing by allowing you to quantify the effects of boat trim, sail trim, wind shifts and current. No more second guessing yourself! Do you hate reading manuals? We specifically designed the SpeedPuck so that almost anyone can figure out how it works in a few minutes without having to read anything