text: The British "Radiac Survey Meter No. 2" dates from 1953 to 1956, and required now-obsolete 15 and 30 volt high voltage batteries and a 1.5 volt standard cell, the latter used to power the valve heater filaments and meter illumination bulb. There was also a training unit, which measured 0–300 mR/h, and ran on four 30 volt batteries plus one 1.5 V cell for the filaments. This meter used a large Geiger–Müller tube, as opposed to the ionisation chamber of the RSM No. 2.
  These meters were favoured, as they had been tested on fallout in Australia after Operation Buffalo nuclear tests, and were retained until 1982 by commissioning a manufacturer to regularly produce special production runs of the obsolete batteries.
  The UK's Royal Observer Corps (ROC) initially used the RSM No. 2 as its prime radiation detector until it was replaced by the specially-designed "Fixed Survey Meter", which used the same obsolete high voltage batteries as the RSM. The ROC retained the RSM No. 2 for use during external "post-attack" mobile monitoring surveys.