What horn buttons fit MTD lawn tractors?

I want to install a horn on my MTD lawn tractor. It has a plastic cap that pops out from the center of the steering wheel. I want to install the horn button in its place but I can't find anything in the stores suitable for this job. I keep finding that same silly chrome button that comes in all horn kits that you can mount with 2 screw. I don't want to use that. I want something that looks professional. I've seen Grant steering wheel buttons but since they're listed for Grant steering wheels they don't list the size so I don't even know if they'll be close enough for me to modify to fit. Any suggestions?