The Bell Explorer is a dual-wave (described in sales literature as 'world wave') version of the Colt.
This was the only dual-wave Bell Colt made, although they did make at least one chassis for Electronic Navigation Ltd in Auckland with a marine SW band (The dial has 'Skipper 10' on it) - and there was a Fountain dual wave radio that appears to have used a dual-wave Colt chassis with a marine band. The chassis has also been seen in the Oak cabinet, but they are predominantly found in the standard Colt plastic case.
Auckland Star 16 July 1959
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.
The radios in this series are: