This is a genuine Porter Cable replacement part, it is sold individually. A Cord Strain Reliever is used on most all power tools. It purpose is to reduce the bending of the cord as it comes out of the housing, which otherwise would cause the cord to crack and wear.
This is an authentic OEM sourced wrench, it is not an aftermarket imitation. It is commonly supplied with miter and circular saws. This wench allows user to install or remove the blade. Angular profile of this item makes tightening and loosening the blade bolt extremely easy. This wrench is made from durable metal material and it is sold individually.