Diameter: 3/8"
Length: 1"
Material: Rubber
Thread Size: 16 (Coarse)
Type: Well Nut

Box of 6.

A well nut is a type of fastener used to blindly fasten a piece and to seal the bolt hole. It consists of a flanged neoprene bushing with a nut embedded in the non-flanged end. The bolt is passed through one of the pieces to be fastened and threaded onto the nut from the flanged end.