LENOX Tools 1991598 T-Shank power Arc® medium metal cutting jig saw blade, 3 5/8-inch X 3/8-inch 18 TPI, 3-pack provides users with up to 2x the life of a straight blade in medium metal and improved blade durability. Curved profile optimizes the angle of attack for fast cutting and longer life Cutting metal. Patented T2™ technology provides fast, efficient cutting in a range of metal cutting applications. Power blast technology® strengthens the blade to reduce breaks and increase durability. Bi-metal technology flexes to resist breaking and extend blade life.