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" (50.8) 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. ASTM D558, D698, AASHTO T99. Shipping wt. 12 lbs. (5.4kg)