The Extech 461830 is a digital StroboTach tachometer. Freeze motion and examine rotating objects without contact. Checks and analyzes motion and speed by simply aiming and synchronizing its flash rate (FPM) with a rotating target. Ideal for determining the speed of moving gears, fans, pumps, motors, and other equipment used in general maintenance, manufacturing, quality control, or laboratories. Comes with a 6-foot power line, a handle, and may be tripod mounted.