"The RAM-B-149Z-QU1 consists of a zinc coated u-bolt base and double socket arm. The mount is designed with a RAM 1"" diameter patented rubber ball and socket system that has adjustment points at both ends of the double socket arm. The zinc coated u-bolt base Accommodates rails from 0.5"" to 1"" in diameter and includes black cover caps to be placed over the exposed ends of the u-bolt. This is a universal mounting solution for the RAM cradles with a 1 inch ball."