Starrett bi metal unique jig saw blades. Bi-metal unique - breakthrough technology provides stronger, longer lasting, faster cutting blades. This new technology joins two strips of high-speed steel wires to a backing steel in a solid phase, using the principle of solid-state diffusion bonding agent - totally different from traditional weld or laser bonding processes that rely on metal diffusion as the union agent at the interface. The proprietary (patent pending) solid-state diffusion process generates 170 percent more weld contact area compared to the existing bi-metal high-speed steels. The result is significantly reduced fracture and breakage at the HSS/backing material interface. Soon after initial use, the teeth develop a groove in the very thin center of backing material at the cutting edge. Multi-Edge Performance, as a result, the cutting stroke produces dual chips that are more easily removed from the cut. For applications utilizing coolant, more of it flows to the cutting surface. This is the Split-Chip Advantage. Lower cost per cut. Application material thickness: 7/32 to 1-1/2-inches. Teeth per inch: 10 TPI. Measures 3-inches cutting length by 5/16-inches width by 0.050-inches thickness. Set type: Tapered, Downstroke Cut. Shank type: Unified. Ground tooth. Curve cut type.