This 2 speed ticket timer is a modern version of tried and tested method of measuring velocity and acceleration. A vibrating striker prints dots on the tape using carbon discs. The unit is housed in hard wearing, inert scratch proof and shock absorbing plastic case and has a single aluminum plate for clamping to the bench or fixing to a dynamics track. It has a unique method of adjusting the position of the carbon disc. 2 speeds 25/s or 45/s Operates on 12 volts DC supply . Includes 2 Rolls of Ticker Timer tape ( PH0353B) and 1 pack of Carbon discs ( PH0353C). Include is a Tape holder that can be mounted on a Lab stand 7/16" Dia rod. This unit kit includes a 7.5" x 6.5" Battery board that holds 8 D Cell batteries for situations that have no external power supply is available. Batteries not included.