The Rotaro T digital hand-tachometer is a device for measuring rotational speed and velocity, as well as length. The compact device has two measuring methods. One is optical, and therefore non-contacting; the other is mechanical using an adapter and various probes. With the optical method, it focuses a beam of light at a thin sticker attached to the object, which reflects it at the speed of rotation. The result appears immediately on the 5-digit LCD. The distance between the rotaro T digital hand tachometer and the test object can be up to 600 mm. The mechanical method uses a contact probe, which is directly attached to the axis of rotation. A measuring wheel is placed on the adapter to measure velocity or length in the normal manner. Using a special adapter, the rotaro T can measure the lenghths and velocities of yarn, wire and glass or other fiber.