461895 combines both contact (0.5 to 19999 rpm) and non-contact (5 to 99999 rpm) models for use in virtually all tachometer applications. Uses visible light for non-contact measurements up to 6 in (150 mm) from target. Comes with wheels for linear surface speed (0.2 to 6560 ft/min, 0.05 to 19999 m/min) or RPM measurements, 4 AA battery, 23 in (0.6 m) reflective tape, carrying case and user manual.