supply of surface hardness testing instrument , surface hardness testing instrument for rail grinding machine. it measures hardnessbefore and after grinding having measuring accuracy (+/-) 4 hld/hldl (0.5% @800 hld/hldl),operating atmosp heric temperature should be -15 degree celsius to +50 degree celsius) and humidity max. 90, resolution 1 hl (leeb), 1 hv (vickers) , 1 hb (brinell), 0.1 hrc (rockwell), 0.1 hrb, 0.1 hs (hardness conversion scales ), hardness results in hlx are often converted to the traditional hardness scales hrc, hb and hv, with powe r input through usb. testing range 150-950 hld 250-970 hldl (native scale). [ warranty period: 30 mon ths after the date of delivery ] ]