The RAM-B-166-UN7U consists of a 3.3" diameter suction cup twist lock base, standard length double socket arm and universal spring loaded X-Grip® cradle for cell phones. The suction cup, twist lock base is designed to have a strong hold on glass and non-porous plastic surfaces. The included X-Grip® cradle has a clean and clever four leg design that sports great holding power without hiding your phone behind foam pads and plastic. The spring loaded X-Grip® cradle expands and contracts, allowing for a perfect custom fit of your cell phone. The perfect complement to the modern sleek interior of today's vehicles, the RAM X-Grip® is the cell phone cradle evolved. The X-Grip® includes a device tether recommended for outdoor applications. The cradle is compatible with handheld devices that will fit the dimensions listed below. It is important to verify the dimensions of your handheld device with a case/sleeve/skin when determining the overall size.