Spring Pins and Retaining Rings are specialized fasterners. Spring Pins are a mechanical fastener used to secure two parts together. Retaining Rings are used to secure components to a shaft usually by installing in a small groove on the shaft body. Retaining rings are a one time use fastener which must be replaced once removed.  Monroe Aerospace is a stocking distributor of Aerospace and Mil-Spec hardware. We have an extensive inventory of spring and retaining rings. Every part that we sell is in Factory new (FN) condition and we provide our company’s certificate of conformance for all parts on every order. See below for our products.