Circular saw blade.
The saw blade is the cutting part of a saw, usually made out of metal with toothed cutting edges. Saw blades come in many different shapes and sizes, from traditional crosscut saws to engine-powered chainsaws. Circular saw blades, consisting of a circular toothed disk spinning at high speeds, are commonly used in the modern industrial age for cutting wood and metal. Saws should not be used by untrained persons without supervision, as accidents with saws have resulted in unwanted amputations.
Sold in hardware stores.