Tachometer, RPM Accuracy +/-0.006 Percent, RPM Resolution 1 RPM, Maximum Contact RPM 25,000 RPM, Minimum Contact RPM 0.8 RPM, Maximum Non-Contact RPM 99,999 RPM, Minimum Non-Contact RPM 6 RPM, Maximum Non-Contact Distance 20 ft, Minimum Non-Contact Distance 1 in, Calibration Certificate Type NIST, Maximum Velocity Measured 25,000 fpm, Minimum Velocity Measured 0.4 fpm, Includes (2) Cone Adapters, 3.5 in Extension Shaft, Contact Adapter, Funnel Adapter, Master Wheel (6 in cir.), Reflective Tape