The IEC 2 speed (25 & 50Hz) DC Recording Timer is very similar to the AC Recording timer, but generates the 25 & 50Hz electronically from an AC or DC source or 12V.AC or DC PlugPak. A microprocessor is used for the job and a slide switch selects the frequency. The heavy diecast base with the rubber feet allows the device to vibrate at 50Hz without the need to clamp it to the bench. The stem from the base permits it to be held on a retort stand for 'falling' experiments. The kit is complete with a 30m roll of white paper and a set of 25 carbon discs for marking the dots on the paper. Large 180m long x 16mm wide paper rolls (PA2670-006) are available together with packs of 100x carbon discs (PA2670-008).