HT-225E Concrete Rebound Hammer Portable Mechanical Hammer Digital Model No. :HT-225E Measuring ranges :10-60MPa Standard impact energy :2.207J ±0.1J (0.225Kgf.m) Rigidity of tension spring :785N/M Stroke of rebound hammer :75mm ±0.3mm The static friction of pointer slider :0.65N ± 0.15N Radius of spherical tip :25mm ± 1mm Average rebound hammer on steel anvil Rm :80±2 Data storage capacity :200 standard components Power supply :1 x 5# Ni-MH rechargeable battery Housing dimensions :54