... is the excellent instrument for assessing test hammer. 2) Test anvil is made from the best ... it and check the rebound value, qualified concrete test hammer will get a average rebound value of ... a calibration instrument, after each 5000 or 8000 test, the test surface can be polished and then continue using, ... must be HRC58~62, or abolish it. 5) Test anvil usually stored in dry dustproof place, protect ...