Abstract: The present invention is directed to a protective device for a nut and bolt assembly which assembly is used to secure two or more parts together. The invention a tubular shaft member to protect the bolt and a tubular shaft or hemispherical body to cover the nut or to cover the tubular shaft and nut together. The tubular shaft is either an independent unit or is integrally connected to the hemispherical body. In more embodiments a connecter unit is used. Grease or other protective agent is introduced into assembly to prevent rust and deterioration.