This is the ideal mounting point for light weight electronics if your rear view mirror has a round arm on the back. The RAM mirror adapter with ball and u-bolt not only looks amazing, but performs beyond expectations. Simply slide the u-bolt over the mirror arm then tighten the bolts to create a light weight, yet durable mount. The versatility of the this base allows the mounting of your device above or below the rear view mirror. The form and function of the RAM mirror adaptor is ideally suited for the mounting of GPS devices, rear view video displays, radar detectors, cell phones, and so much more. The base includes black cover caps to be placed over the exposed ends of the u-bolt. The included composite reduction shim can narrow the rail to a minimum width of 0.5". The mirror base will attach to all RAM "B" size double socket arms.