I bought the wheel from Shell Valley actually. The adapter is from Summit Racing (
ididit 2201310040 - ididit Steering Wheel Adapters - Overview - SummitRacing.com).
I know that the original horn button that came with adapter said Lecarra on it, which is why I made the assumption that the aluminum one in the picture would fit. I wouldn't be surprised if the steering wheel is Lecarra, but I'd have to check. I can try to measure my wheel for you, if you want?
Sorry I didn't respond sooner, but I don't check this forum as often as I'd like to. You can shoot me an email too, if you want.
Fritz