1) Center guide rod using imported materials, high precision, wear resistant;2) Use of super-hard aluminum shell to avoid on. ExplanationConsistent withGB/T9138-1988 standards and JJG817-93 statutes and JGJ/T23-2001 technical regulations.HT-225B Concrete Test Hammer generally applied to building components, bridges and all kinds of concrete components (panels, beams, columns, bridges) strength. ...