Tachometer, RPM Accuracy +/-0.05 Percent, RPM Resolution 0.001 RPM, Maximum Contact RPM 20,000 RPM, Calibration Certificate Type NIST, Maximum Velocity Measured 6,562 fpm, Minimum Velocity Measured 0.16 fpm, Includes Timer and 12 in of T-5 Reflective Tape, Totalizer, Features Auto Ranging/Fixed Decimal (User Selectable), English and Metric Rates, On-Target Alerts, Rubberized Housing, Tripod Mounting Bushing, TTL Pulse Output (Requires Optional 6-Foot BNC Cable)