text: The 1958–1959 "Quartz Fibre Dosimeter Chargers, No. 1 and 2" were retained until the early 1990s, as they incorporate a simple, handle-driven generator and do not require batteries at all. A later British civil defence dosimeter charger was developed by R. A. Stephen Ltd and manufactured from 1967 to 1988, and uses a single 1.5 volt cell.  It is similar to American dosimeter chargers.