These Starrett hacksaw blades offer optimum cutting performance across a broad range of materials. A patented solid state diffusion process is responsible for producing the industry?s most advanced bi-metal hacksaw blades. Increase in tooth strength and reduction in breakage and fracture. Good for interrupted cuts in cramped places or where the blade may bend or experience twisting stresses. | ? 18 TPI | ? Reduction in breakages | ? Increase in tooth strength