When fitting the electronic distributor I bought from E-bay I found there was no rotor button. I tried both the gh600 & gh606 buttons & both were to big to fit the shaft. They would turn 360 degrees & would not lock the button in place. I got the car running by bodging one of the buttons, but needed a permanent solution, because it was a real dodgy fix. Emailing the supplier did no good, so I replaced the distributor with an N12 dizzy, then took the new distributor to Stuart at SWR. He said the distributors were made for forklifts, so maybe a forklift supplier had parts to fit. I found such a distributor & he was able to supply 2 different buttons, one taller than the other. Both fit the shaft perfectly. Unfortunately I have lost the piece of paper with the parts numbers, but if you have bought one of these distributors, at least you should be able to find rotor buttons & even distributor caps.