Metal Series Cobalt Bi-Metal Reciprocating Saw Blades. Metal Series Blades Are Professional Bi-Metal Blades With Cobalt High Speed Steel Teeth And Shatterproof Shock Absorbing Alloy Backbone. 1″ Width And Heavy Duty Blade Thickness For Clean Cuts With Less Vibration In Heavy Metal Cutting Applications. 1/2″ Universal Shank With 5% Tilt Angle For Faster Cuts And Skid Free Starts. Lasts 20X Longer Than Standard Bi-Metal Blades In Metal Applications.