Description: Smith & Wesson M&P Shield 9 / 40 Recoil Spring Assembly. This durable, steel constructed, recoil spring assembly is a factory original part from Smith & Wesson. The assembly is designed for the M&P Shield 9 / 40 models of pistols from Smith & Wesson chambered in 9mm & .40 S&W respectively. The recoil guide rod assembly helps mitigate the felt recoil of the pistol when fired and absorbs much of the backward force along with helping to cycle the firearm. This assembly is perfect for use in an emergency replacement stash and can be great to have in the spare parts chest. This item is proudly made in the USA by Smith & Wesson.