Need info on a 75¢ coin mech!

I have a few of these 75 cent coin mechanisms, but I really don't know anything about it. I don't think it's that old, and can't find any manufacturer mark. All I see is "made in china". It's pretty heavy, with the bottom measuring what looks like just shy of 4 1/4 inches. Its widest part looks to be around 5 1/4 inches. There are a couple of grooves on each side where it looks like it would slide into the machine. Are these a "standard" size? Or would these go to a specific machine? I would greatly appreciate any info anyone can provide, or at least point me on where to go to get more info.