We R Memory Keepers Crop-A-Dile Corner Chomper 1/4 Inch Punch

“This amazing tool is a 2-in-1 corner rounder that cuts both 1/4" and 1/2" rounded corners on your projects to give them a clean and finished look. You'll love that it holds the cut pieces in a waste receptacle until you're finished punching. And the corner guide will help you see exactly where you're cutting. Once you've completed your project simply fold the tool flat and it's ready to be stored until the next time you need it.”