For the measurement of velocity and acceleration, using timing marks made on a moving self-marking paper tape by a vibrating ‘striker’. Designed to operate on a 12V AC supply and uses the mains frequency as its timing standard. The unit is housed on a metal base 30 x 16 cm. The base also carries a tape guide which incorporates a self-marking paper tape. Pair of 4mm sockets is provided on the side of the case for connection to the electrical supply. Supplied with a roll of 50m of self-marking paper tape, 15 mm wide.