The Lenox Tools 20295CF450SR T-Shank High Carbon Steel Down Cut Jig Saw Blade 4-Inch x 5/16-Inch 10TPI - 5 Pack provides users with a clean smooth cut in wood. The 10 TPI allow you to cut quickly on the down stroke, while the sharpness of the carbon steel and the precision ground teeth give you a nice clean finish. The teeth are ground to precision sharpness for straight cuts. These blades are made specifically for jig saws that take T-Shanks.