I tried a Austin Healey hydraulic brake switch I had in the parts collection and it fits the Commando brake master cylinder perfectly. The advantage is it is slightly smaller than the original so the boot fits better and it is less than $12.45 new verses $30 plus from some MC dealers. The switch is a "Intermotor" and their part # is 51630 available at most Auto parts stores. Moss Motors carries them and their catalogue part # is 560-480. It also does not take much pressure for this switch to activate the brake light.