Abstract: Fasteners such as bolts or nuts are locked by a ring and associated keys. The ring typically has a series of holes with the fasteners passing through these holes in the ring. The ring has an outer surface with studs extending upward therefrom. Typically one key for each fastener is placed adjacent to the ring after the fasteners are tightened against the ring in each hole of the ring. The key has a head opening which fits over a head of the fastener and keeps the fastener from rotating. The key also has a bore which fits upon the stud, with the stud preventing key rotation, and the key in turn preventing fastener rotation. A retainer such as a lock nut on a threaded stud or a snap ring in a grooved stud hold the key to the ring and keep the ring in position locking the fasteners.