This was the second bit of amateur radio equipment that was produced by TW (the TW2 transmitter being the first).
This crystal controlled valved converter used a 6BQ7A as its RF amplifier, had a silver plated chassis and had a noise factor usually better than 4 to 5db. It was available with a choice of I.F.s. and a separate power supply was also available. Although many of these units were produced, it was eventually superseded by the Nuvistor converter.
The converter was available for 2m and 4m and sold in September 1960 for the princely sum of 11gns and the separate P.S.U. for 4gns.