The Extech 461895 tachometer combines both contact (0.5 to 19,999 rpm) and non-contact (5 to 99,999 rpm) models for use in virtually any tachometer application. The meter uses visible light for non-contact measurements at a distance of up to 150 mm (6 inches) from the target. The wheels are suitable for linear surface speed (00.05 to 1999.9 m/min, 0.2 to 6560 ft./min) or RPM measurement. The scope of delivery includes four AA batteries, a 0.6 m (23 inch) reflective tape and a carrying case.