The ZC1 remote control unit (and the Australian equivalent) is basically a locally produced version of the British "Wireless Remote Control Unit 'A'", for Wireless sets 1 and 11.
The Canadian one is rather later, and intended for the W.S.19 and 52, based on the British Remote Control Unit "B" for the WS9 (later converted to the 'E' for the WS19 and WS52).
I think the British ones got as far as 'Q', but the common ones are the E Mk.I (wooden case), Mk.II (steel case), the Canadian No.1, and the 'L' (No.1 & No.2) pair of units for the WS62.
(This should really all go in the Wireless rather than the For Sale section.)
