RAM Mount 4.75" Square Base VESA Plate 75mm and 100mm Hole Patterns w/Short Arm Surface Mount [RAM-101U-B-246]The RAM 101U B 246 consists of a short double socket arm, 2. 5" diameter round base with the universal AMPS hole pattern and 4. 75" square plate with the VESA hole pattern. The VESA plate contains a 75mm X 75mm and 100mm X 100mm hole pattern. Designed into the mount is a 1. 5" diameter patented rubber ball and socket system with adjustment points at both socket ends of the arm. Rubber ball and socket technology allows for almost infinite adjustment