Bi-metals Reciprocating Saw Blades are a combination of both high carbon steel and high speed steel and are suitable for thin sheet metal, man made board, woods with nails, and plastic. These are a tougher shatter resistant blade that keeps its edge for longer. Teeth type are Milled & Slide Set, with teeth pitch of 4.3mm and have a tpi 6.  Sold in packs of 5.