Universal tablet holder, top quality. Rubber pads enable a firm, stable grip. Round/square shapes: 1.58 to 3.81 cm. Flat shapes: 0 to 2.9 cm. Ball joint: 1.5 inch rubber ball. Dimensions: 3 (W) x 12.2 (H) cm, 181 g. The RAM Mount holding system is modular in design. Each holder consists of a base, an arm, and a headpiece. Depending on the holder, these components are either screwed together or typically connected via a ball joint. This provides flexibility in positioning and, along with the material, offers shock and vibration dampening effects.