... Contact Tachometer DT2235A contact tach:0.5-19,999 rpm, surface speed:0.05-1,999.9m/min Digital Contact TachometerModel ... : CONTACT TACH: 0.5~19,999RPM SURFACE SPEED: 0.05~1,999,9m/min SURFACE SPEED: 0.2~6,560ft/minResolution:CONTACT ... :0.1RPM(0.5~999.9RPM)1RPM(over 1,000RPM)SURFACE SPEED:0.01m/min(0.05~99.99m/min)0 ... .1m/min(over 100m/min)SURFACE SPEED:0.1ft/min(0.1~999.9ft/min)1ft ...