SPECIFICATIONS:HT-225A ( BOX ALUMINIUM ) Nominal kinetic energy : 2.207J (0.225 kgf.m) Flip tension spring rigidity : 7.84N (0.80 kgf) / cm Punch advance for impact hammer : 75 mm Impact surface hardness value between impact hammer and rod : HRC59-63 Maximum breakout friction of pointer system : 0.49-0.78N(50-80g) Mean-value of steel-anvil rating of concrete test hammer : 80+/-2 Standards : ISO/DIS 8045, EN 12504-2, ENV 206, DIN 1048 part 2, ASTM C 805, ASTM D 5873, NFP 18-417, B 15-225, JGJ/T 23-2001, JJG 817-1993 Dimension : 60 x 280 mm