The 3-5/8 in. SAWZALL Blades for Metal are made with matrix II bi-metal teeth to keep a sharper tooth edge longer. The tough matrix bi-metal teeth allows for faster cutting and longer life with blades that bend without shattering. The double relief angle reduces tooth stress for longer blade life. Milwaukee designed the material, blade geometry and heat treating to maximize metal cutting performance in the toughest professional applications. These SAWZALL metal blades have 1/2" universal tangs for versatility.