Perform Tachometer RPM measurement, Stroboscopic speed and motion analysis with the 461825 Combination Photo Tachometer and Stroboscope. Unique display reverses character direction depending on which measurement mode you are using. Tachometer memory stores last, max and min readings for recall. Strobe features course and fine flash rate adjustments in 3 ranges. Complete with 4 AA batteries, reflective tape, and carrying case.