BLADE SAW RECIPRO METAL 6"18T. The Bi-Metal reciprocating saw blade is perfect for cutting difficult materials such as wood with nails, for example. It features an 8 percent cobalt edge, bimetal construction, precision milled teeth, making it resistant to high wear and tear. Its blade is bimetallic to ensure a longer useful life of the blade itself. Your tooth is designed to last longer and cut through stronger materials.