These digital, portable tachometers provide a nonslip, rubber grip for single-hand operation. Tachometers feature user-selectable fixed or auto-ranging resolution, memory of last reading, minimum and maximum, tripod mounting Bushing for hands-free operation, target "lock on" indicator, and a low-battery indicator. AO-08199-20 08199-20 features a red LED that measures optical RPM from up to 30" (76.2 cm) away. Models 08199-22 and -24 feature a Class II laser that measures RPM from up to 25 feet (7.6 m) away. These tachometers function as a Totalizer/counter and a timer (stopwatch) programmable in both English and metric units. AO-08199-20 08199-24 adds the functionality of measuring contact RPM and surface speed. What's included: AO-08199-20 08199-20 includes 12" (30.5 cm) reflective tape. AO-08199-20 08199-22 includes 12" (30.5 reflective tape and nist-traceable calibration report supplied by the manufacturer. AO-08199-20 08199-24 includes remote contact assembly with concave and Convex tips, 10-cm speed wheel, 5 ft (1.5 m) of reflective tape, nist-traceable calibration report supplied by the manufacturer, and a carrying case. Ergonomic design allows simultaneous viewing of both the target and display rugged, Rubberized design for industrial applications.