... :ModelHZ-2507A PHR Protable rockwell hardness gaugeHardness scaleRockweel—A, B , C , D , E , F , G , H , KSuperficial rockwell—15N , 30N , 45N ... ballF60BBronze, phosphor bronze, malleable iron, etc. (HRB value of nearly 100 materials).1/16 steel ballG150BAluminum, zinc, lead and soft metals ...