Comprising a 24 swg. constantan wire stretched along a metre scale, subdivided in centimetres and mms, clamped to stout under heavy plated brass plates of SWG 18 and fitted by screws in such a manner so that leaving virtually no margin for 'end errors '. The terminating strips are provided with heavy duty  terminals and the whole is mounted on a  polished hardwood board. Supplied with Pencil Jockey along with lead for connections.