These are the top quality scroll saw blades woodworkers ask for by name - OLSON! These 5" metal cutting scroll saw blades are made specifically for power scroll saws, unlike brittle jewelers or metal piercing blades intended for use in hand held frames. These blades are made from hardened and tempered steel and have more teeth per inch than regular scroll saw blades for cutting thin metal and other hard materials. Universal No. = 7, Width =.041", Thickness =.019", TPI = 30. Designed for cutting thin metal .100" thick.