A hand-held, battery-powered instrument used to measure and establish rotational speeds of a rotating device or device component (e.g., an electrically-powered motor). It has a coned rubber tip at the distal end which is brought into contact with the centre of the spinning object (usually a shaft) by the user. The rotational motion is electronically detected and a reading, typically in revolutions per minute (rpm), will appear on the digital display. The device may be able to convert and display the results in other units such as foot/second or inches/second. The device will typically be able to store a number of readings within its memory.