CB antenna tuner 100TU27 from `Oscar One' 27 MHz f.m. CB mobile/base radio transceiver, manufactured by South Midlands Communications Limited, Eastleigh, Hampshire, England, 1980-1983.
This radio transceiver set was designed to be used on Citizens' Band (CB) frequencies - radio channels there could be used by amateurs. These were legalised 1981, but had been used illegally in previous years. Until 2006, CB radios required licences, which could be purchased from the Post Office.