Installing crown molding is one of the best ways to add instant value to your home. The Kreg Crown-Pro™ simplifies the most frustrating steps of the process so you make fewer mistakes and get the job done faster! This uniquely designed tool holds your trim at the exact angle required, eliminating the need for advanced compound miter cuts and difficult 'coping'. It's unique curved design lets you compensate for a wide variety of crown molding spring angles, and it's extension arms let you work with crown up to 5-1/2" wide.10” saws will work with crown up to 3-1/2” wide, depending on manufacturer.12” saws will work with crown up to 5-1/2” wide, depending on manufacturer.