Geartist (TM) GT8905 Professional Digital Photo Tachometer Non Contact RPM Tach Measurement range: 2.5~99999 RPM, Range Select: Auto-range Accuracy: (0.1%+5 digit) 2.5-999.9RPM; (1%+5 digit) 1000-99999RPM Resolution: 0.1 RPM (2.5~999.9RPM); 1 RPM (above 1000RPM) Non-contact Detecting Distance: 50mm-500mm 5 digits LCD, Time Base: Quartz crystal, Sampling Time: 1 TIME / SECOND