LENOX Tools 1990846 U-Shank clean wood cutting jig saw blade, 4-inch x 5/16-inch 6 TPI, 5-Pack provides users with improved blade durability and clean, smooth cuts in wood. Power Blast technology® strengthens the blade to reduce breaks and increase durability. Precision ground teeth with optimized tooth angles provide a clean finish. Bi-metal technology flexes to resist breaking and extend blade life.