The X-Grip Holder With Motorcycle Stem Base With Ball Kit consists of a fork stem base, short double socket arm and universal X-Grip® cradle. 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 X-Grip® includes a device tether recommended for outdoor applications. This part is designed to fit into the cylindrical bore wall of fork stems and will work with stems that measure from 12 - 38 mm (0.5" - 1.49"). High-strength composite, marine-grade stainless steel and powder-coated marine-grade aluminum. The cradle is compatible with handheld devices that will fit the dimensions listed below. Cradle Dimensions: Minimum width = 1.875" (minimum height = 4.25").