Tachometer, RPM Accuracy +/- 0.006 Percent, RPM Resolution 1 RPM, Maximum Contact RPM 25, 000 RPM, Minimum Contact RPM 0.1 RPM, Maximum Non-Contact RPM Not Applicable, Minimum Non-Contact RPM Not Applicable, Maximum Non-Contact Distance Not Applicable, Minimum Non-Contact Distance Not Applicable, Calibration Certificate Type NIST, Maximum Velocity Measured 12, 500 fpm, Minimum Velocity Measured 0.05 fpm