Jumbo, Mini Jumbo & Mega Jumbo Jaws are large, flat aluminum plates. Rubber bumpers serve as padded jaws for positive, non-marring holding of nearly finished turnings. They hold objects too large for any other chuck, and they're especially useful for reverse chucking bowls. Each set comes with 8 steel-cored rubber bumpers sufficient for almost any need. Additional sets of 8 bumpers are available, and come with long screws so two bumpers can be stacked for extra holding power. Mini Jumbo Jaws are designed especially to work on mini lathes with swing as little as 10".