This extremely popular unit has revolutionised experiments of the quality of the traces it makes, and the reliability of the mechanism. There is no double-dotting or smearing even at high speeds. No pen or carbon disc is required, friction between the tape and the ticker- timer is kept to a minimum excellent results can be expected, even in a ‘g’ by free -fall “. Experiment. The unit is supplied with a clamping rod and fixing point so that. It can be mounted vertically in a retort stand. Self marking tape is not included. Requires 2V AC, from a low voltage power supply.