This ejector spring is coiled from strong steel to provide a long service life and is a factory original component from Mossberg. Designed to fit the Mossberg Patriot, MVP 5.56 & 7.62 Action, 4X4, & 100 ATR rifle model, this ejector spring provides pressure to the ejector from proper expulsion of cartridges after the bolt opens. This spring is perfect for replacing your worn / missing component or to keep one as a backup in the spares chest. Mossberg small parts are made to the same high material and workmanship standard that you have come to expect and trust from Mossberg for your firearm.