Clutch Identification

I found this primary last week while cleaning out a shed. Didn't know anything about it, other than that it was a spare that had sat in there for many years. Appeared to be complete and in working condition, so I saved it from a load of scrap iron.

I did some research...turns out it is a St. Lawrence, made in the early '70s. I understand that St. Lawrence was something of an aftermarket clutch? I also read that it was optional factory equipment on the Arctic Cat Puma.

Anyone have...

Clutch Identification