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.