twin cable release for £2

To release shutters simultaneously on two Canon EOS's;
1. buy 2 cheap cable releases (RS-80N3 for 10D, 5D, 1D costs just 99p on ebay from China!).

2. remove 3 connecting wires from one switch box and solder onto the corresponding contacts in the other (wires are colour coordinated and the 'Shoot' release I purchased even had spare contacts to solder onto).

3. use a craft knife or file to extend the opening to accomodate the second cable.

4. put back together after ensuring that the 3 new wires will not slip between the switch contacts (I used sticky tape to keep them to one side of the box).

That's it!