A solid insert that is threaded on the outside with wedges (keys) attached to the top of the insert. After the part is re-threaded, the insert is screwed into the part and the wedges are driven down into the tapped threads to keep the insert from turning in either direction. These inserts are available in thin wall, heavy duty, or extra heavy duty thicknesses, in either coarse or fine thread. The standard materials are either C1215 carbon steel or 303 stainless steel, although other materials are available, such as A286 stainless steel, 316 stainless steel, or 4140 alloy. In addition to the standard style, the inserts are also available in an internal locking style, which will lock the bolt into the insert.