The RAM-347U consists of a 1.5 diameter rubber ball connected at right angles to a 2 x 1.7 rectangle base. The base has four pre-drilled holes at each corner, making the universal AMPS hole pattern. Product Features: Rectangular plate features the AMPS hole pattern for connection to a wide variety of devices Included C size 1.5 RAM® rubber ball allows for connection to any C size RAM® double socket arm; ball and socket technology allows for near-infinite adjustability Made of powder-coated, marine-grade aluminum for durability and reliability in the most demanding environments Backed by a lifetime warranty