Bracket Handle (Finding Neverland)
Useful for demonstrating colour mixing concepts.
The Lock offs do not disengage (or declutch) when you reach the top or bottom of dimmer travel. You have to unscrew them when they reach end of travel.
This board is marked up to use sequential dimmer numbers, but earlier versions would have used geographic dimmer labelling (based on location within the theatre).
Black labels + / - a third (750W +/- a third gives you 500W or 1000W load), with a different dimmer curve. Other dimmers were wound for a specific wattage.
Switches - Battleship switches - 3 position double pole. Extra spring-loaded switch.