JIS B 7529:2017 specifies the vapour pressure thermometers (hereafter referred to as thermometers) consisting of a Bourdon tube and a temperature sensitive cylinder connected with each other by a conduit tube, and filled with a volatile liquid. The indicator in a round case has been a single pointer and scales concentrically marked on the dial. The pressure change caused by the vapour pressure change of the volatile liquid contained in the system according to the temperature change at the temperature sensitive part is converted to a mechanical displacement of the pointer to indicate the temperature. The thermometers are used in the temperature range of -30 °C to +200 °C.