Over the years we have developed and refined a special manufacturing process designed to lengthen blade life. These are the blades good enough to be called Morse. These extra-tough, professional quality blades are available for a wide variety of uses in wood, metal, plastics, fiberglass, plaster and other common building materials. We electron beam weld the Matrix II cutting edge to the backer so that we can control the process and guarantee quality. Fits all popular reciprocating saw machines.