4 valves and a silicon bridge rectifier. Around this time Bell switched to transistors and there were no further valve-based Colts produced - this was the last model with the warm glow.
Generally easily spotted by the black-painted badge riveted on the rear. There is space for a model code on this badge, but no examples have yet been seen with the code stamped in. The other identifying feature is the power transformer being mounted on an angle.
Bell Colts ran from 1951 through until 1980 - the longest running model of NZ built domestic radio. It saw many different engineering changes over the years, and the last few models dropped valves in favour of new transistor technology. There is considerable information on the main Colt page about this Kiwi icon.
The radios in this series are: