Contact And Non-Contact Tachometer, Range: Surface Speed (Contact): 0.1 - 1999 M MINT, 0.4 - 6550 FT MINT, Rpm Range: Rotation (Non-Contact): 1 - 99999 RPM: Rotation (Contact): 19 - 19999 RPM, Accuracy: Plus- Minus (0.02 PCT V Reading Plus- Minus1 Digit), Working Distance: 600 MM Maximum (Optical),