Description 43717 Wolff Glock 17 20 21 22 24 34 35 Factory Standard Recoil Spring Wolff recoil springs for use in Glock pistols are available with load-rated specifications to tailor the recoil function to individual needs. Due to the design of the Glock pistol, all Glock recoil springs now include a factory strength replacement striker spring.    NOTE: Wolff recoil springs for Glock pistols are not captive. We highly recommend using them in  conjunction with Wolff guide rods listed below.   Note: Not for use in Generation 4 pistols.   For Use In:      Glock 17, 17L, & 34, 9mm       Glock 20, 10mm       Glock 21, .45 ACP       Glock 22, 24 & 35, .40 S&W       Glock 31, .357 Sig       Please See Ratings Below  •Reduced Power…: 10, 11, 12, 14, 15 & 16 Lb.  •Factory Standard.: 17 Lb.  •Extra Power………: 19, 20, 22 & 24 Lb.    IMPORTANT NOTE:  Factory recoil spring ratings above are for current production models with captive factory recoil spring systems which are silver/gray in color. Previous captive factory recoil assemblies for the 17, 17L, 20, 21 & 22 had recoil springs rated at 16 pounds. Earlier non-captive models of the 17, 17L and 19 had factory recoil springs rated at 19 pounds. Not for use in Generation 4 pistols.