Supports the following standards: ASTM D3877, ASTM D5102, ASTM D558, ASTM D560, ASTM D698, ASTM D3282, AASHTO T99 Manual, moisture/density hammer meets ASTM and AASHTO specs. It incorporates a 5.5 lb (2.54kg) weight and a drop of 12" (305mm) with a 2" (51) face. Guide sleeve has four vent holes in each end of sleeve to release built-up air pressure. Machined steel, plated for rust resistance. Features resilient rubber ball handle.