The RAP-274-1-GA40 consists of the EZ-ON/OFF dual strap base, swivel diamond adapter base and high strength composite cradle for Garmin GPSMAP 78 series devices. Adjust the zip ties to attach to a variety of rails, from a minimum of 0.5″ in diameter. With a press on the diamond adapter the EZ-ON/OFF system allows for the quick release of the Garmin GPSMAP cradle from the base. When connected, the diamond base can rotate, allowing for you to position the Garmin GPSMAP cradle for optimum viewing.