Never use a knife again to finish a buttonhole. Punch a perfect buttonhole every time with this high quality punch. If you use button studs with your projects, this is a tool you'll want to be sure to add to your workshop. Punch is designed to fit 8mm Button Studs #11310. Protect the investment in your tools but using a high quality, impact absorbing surface underneath your leather while punching holes, see Poly Boards #3464-152.