Bosch 5 In. x 5 In. SDS-max Tamper Plate Hammer Steel HS1828 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.