The 4-inch Hikoki Cut-Off Wheel is a type of abrasive cutting disc designed to be used with handheld angle grinders or cut-off machines. Hikoki, formerly known as Hitachi Power Tools, is a Japanese manufacturer of power tools and accessories. This is made of abrasive materials, such as aluminum oxide or silicon carbide, which are bonded together with a resin or ceramic material. The abrasive materials of the 4-inch Hikoki Cut-Off Wheel are evenly distributed throughout the disc and provide a cutting edge that can quickly and easily cut through a variety of materials, including metal, concrete, and masonry.