RAM Tab-Tite Drill-Down Mount with Backing Plate for Small Tablets RAM Tab-Tite Drill-Down Mount with Backing Plate for Small Tablets (RAM-B-138-TAB4-225BU)The RAM-B-138-TAB4-225BU consists of a 3" x 3" backer plate, double socket arm, round base adapter and Tab-Tite universal clamping cradle.