This is a genuine part that is supplied by the original manufacturer for use with Powermatic spiral cutter head planers. The wheels are attached to the bottom of the planer and are used for transporting it from place to place. This part is made of plastic and metal and is sold individually, though three are required for the unit. For installation, you will need a socket wrench and a screwdriver to aid you. For Use With: Jet 15S (1791210) 15" Spiral Cutterhead Planer 15HH (1791213) 15" Helical Cutterhead Planer