This is an authentic Porter Cable replacement part, sourced from the original manufacturer for use with miter saws. The special blade wrench is commonly used when changing the miter saw's blade. Most miter saw blade bolts are left hand threaded and to loosen the bolt the wrench needs to be turned clockwise, please consult the saw's owner's manual. This blade wrench is available as an individual replacement part.
This is a genuine OEM replacement part designed for use with a variety of power tools. It is made out of metal and it is sold individually. It is a standard hardware which has multiple applications based on your tool. You would need a wrench to tighten/loosen this nut.