* U-shank jig saw blade sets offer ideal assortments* High carbon steel (HCS) blades are best in softer materials such as wood, laminated chipboard and plastics* High speed steel (HSS) blades are used in metal, aluminum and non-ferrous metal* Bi-metal blades are highly flexible and tough because of a combination of HSS and HCS. Suitable for the most demanding applications when there is a risk of shank breakage or when extremely versatile blades are required. Bosch bi-metal jig saw blades last twice as long as HSS blades and 10 times longer than HCS blades. Used for wood, metal, non-ferrous metals and aluminum* 1/4? universal shank (U-shank) blades suitable for jig saws from Skil, Black & Decker and others