Ram Mount X-Grip Phone Mount w/Track BallBase [RAP-HOL-UN7B-354-TRA1U]RAM X Grip Phone Mount with Track BallBase The RAP HOL UN7B 354 TRA1 consists of a Track Ball base, composite double socket arm and universal spring loaded X Grip cradle for cell phones. This design features a 1" diameter rubber ball and socket system with adjustment points at both ends of the socket arm. The spring loaded X Grip cradle expands and contracts, allowing for a seamless fit with your phone. The kit is the perfect complement to the modern