LENOX Tools 1991561 T-Shank thick metal cutting jig saw blade, 3 5/8-inch X 3/8-inch 14 TPI, 25-pack provides users with improved blade durability and long life in thick metal. Power Blast technology® strengthens the blade to reduce breaks and increase durability. Patented T2™ technology provides fast, efficient cutting in a range of metal cutting applications. Bi-metal technology flexes to resist breaking and extend blade life.