Bi-Metal (B) - Long Life Blade - features high speed steel ( HSS ) hardened teeth ( 18 TPI ). This type of blade is suitable for harder wood, copper ( copper pipes ), aluminium, fibreglass, plasterboard,nail embedded wood，tubing, PVC, hard plastic ( acrylics, plexiglas ) and non-ferrous metals. The hardened teeth ensure a longer life compared to standard carbon based blades..Oscillating Saw Blades Kit: Contains 50 pack 1-3/8-Inch BI-Metal oscillating tool blades. These oscillating saw blades can meet a variety of needs, which could be used professionally for workshop ,household or other place..Universal Compatible System: Our quick release saw blades are compatible with many oscillating tools in the market, such as Black&Decker, Craftsman, Chicago Electric, Fein Multimaster, Milwaukee, Hitachi, Dewalt and More..Special Design for Precision cutting: Built-in length markers on two sides, one side is Inch and other is Millimeter, ensure you can get accurate cuts easy and fast while you working with it. Manufactured with a durable cutting edge that resists wear and cuts quickly.