Bosch 8 In. x 8 In. Tamper Plate 1-1/8 In. Hex Hammer Steel HS2125 EFFICIENT: The Bosch Tamper Plate efficiently compacts backfill and gravel, and combined with the tamper plate shank for tough hammer steel. COMPATIBLE: It works with a variety of hammer shank systems  SDS-max, spline/round hex and 3/4 In. hex.