The easy-to-use and read YELLOW JACKET® Tachometer unit measures 10 to 99,999 RPM on compressors, fans, motors, gears, pulleys, and more. A non-contact reading maintains torque and precise measurement. Features of the YELLOW JACKET® Tachometer include: auto range function; non-sleep mode and hold function; measure and read with the press of a button; low battery indicator; units in RPM; hold function to freeze rotating speed; readings to a resolution of 0.001 RPM; and, sampling time of 1 second (>60 rpm, 10 to 60 rpm).