Small: 3/8" (9.5 mm) diameter barrel with a 1/4" (6.3 mm) wide angle detail blade.Large: 1/2" (12.7 mm) diameter barrel with a 3/8" (9.5 mm) wide hollow ground blade.When you are looking to upgrade the quality of your swivel knife, the Craftool� Pro is the one to choose. This stainless steel swivel knife is designed for a lot of regular use. The ball bearing swivel makes the contoured yoke turn smoothly, making it the perfect choice for the professional leather craftsman.