The RAP-274-1-MA15U consists of the EZ-ON/OFF dual strap base, swivel diamond adapter base aand custom high strength composite cradle for the Magellan eXplorist GC/110/310/350H series. Adjust the zip ties to attach to any rail from 0.5' to 1.5' in diameter. By simply pressing and twisting the diamond adapter, the EZ-ON/OFF system allows for the quick release of the Magellan cradle from the zip tie base. When connected, the diamond base can rotate, allowing for you to position the Magellan device for optimum viewing. This mount includes a 12 degree tappered shaft for tapered handlebars.