Spark Timer Replacement Carbon Disc

These are replacement carbon disc for the Spark Timer (TKTMR). The Spark Timer is a recording device used to measure the velocity and acceleration of a falling or moving object. It sparks at uniform intervals, leaving marks on a paper tape. The distance between the marks on the tape are used to calculate velocity and acceleration. It is provided with a roll of tape, a carbon disc, and a clamp to hold it in position.