Ed, the self cancelling unit is also the flasher and it is electronic. It is about 1/4" thick by 2" long and perhaps and inch or so wide, so very tiny for installation inside the battery box or in the headlight bucket. The inputs requires a momentary contact type switch. You could have one switch that was spring loaded to return to the centre off position,. I am still looking for a switch of this type, might have to alter some other kind of switch.
I used a small red kill button type switch either side.
Depress the button for one second and you get 7 flashes, ideal for changing lanes on a highway or motorway, depress the button for two seconds and you get 15 flashes, ideal for rolling thru a left hand or right hand turn on a green light, depress the button for three seconds and the flashers stay on for 60 flashes, which works for sitting at a light.
Depress both buttons at once and the hazards come on and stay on until you push both buttons at once again. So the two buttons are needed to access the hazard function, one self centering momentary switch will only work for the indicators
Glen.