Garmin Ground Speed Sensor use in farming and electronics applications that require a small, highly accurate GPS receiver. This 12-parallel-channel, WAAS-enabled GPS receiver comes with an integrated magnetic base, and converts the NMEA string to a radar pulse. The Hockey Puck  weighs just a few ounces, making it an ideal solution for applications where space is at a premium and is customizable to meet your needs. Garmin  

Note: Lead Length between Mushroom and Box is 13 Feet.