Ball Mount, 1", MFG# RAM-B-111, consists of a double socket arm, 2.5" diameter round base and 6.25" x 2" rectangle base, which contains different combinations of pre-drilled holes for Marine GPS, CB Radios, Ham Radios, Gimbal Brackets and more.Specifications and Features: 6.25" x 2" rectangle base and a 2.5" round base Allows you to mount a range of objects to various locations on your boat Double-socket arm lets you reposition electronic devices easily Made of powder-coat, marine-grade aluminum for durability Predrilled holes in different combinations on both bases allow convenient installation and mounting options for fishfinders, CB radios, gimbal brackets and more Universal AMPS hole pattern