The Taylor Freelance +5 magazine for the Smith & Wesson M&P 9mm Luger/ 40 S&W pistol is constructed of aircraft aluminum with a black anodized finish. This magazine extension will increase the capacity of your factory magazine by 5 rounds in 9mm and 4 rounds in 40 S&W. The length of the magazine with the extension will not exceed the IPSC 140mm length rule when used on full size M&P magazines. The extension works with the stock magazine follower and includes an ISMI extra power spring for reliable operation.