Kotflügelhalter

A retainer is a part that holds another component in its correct position and stops it coming loose.

It locks a bearing, seal, spring, or shaft in place against the forces of operation, often as a ring, clip, plate, or cap.

Retainers are used wherever a part must be held in place — hubs, gearboxes, and many assemblies. The correct retainer matches the part it secures.