Check the listing for details. ISMI Guide Rod Recoil Springs For GLOCK Models 17 19 20 Gen 1 2 3. Condition: New. Listed at 8.85 USD. DESCRIPTION ISMI recoil springs are wound from flat wire so they are a direct replacement for your factory supplied springs. Manufactured from certified Aerospace specification materials. All springs are heat treated, shot peened and stress relieved for maximum durability. ISMI employs ISO 9002 quality control standards. Includes a 12 month manufactures replacement warranty. RECOIL SPRING WEIGHT BY MODEL FITS GLOCK MODELS- 17,17L,19,20,20SF,21,21SF,22,23,24,31,32,34,35,37,38 GLOCK FACTORY SPRING WEIGHT IS 17lbs for G17, 17L, 20, 20SF 21, 21SF, 22, 24,31,34,35,37 GLOCK FACTORY SPRING WEIGHT IS 18lbs for G19,23,32,38 RECOIL SPRING WEIGHT USAGE 11 - 13 LB SPRINGS ARE MOSTLY USED FOR COMPETITION SHOOTING, OR IF USING A RECOIL COMPENSATOR ON YOUR BARREL. LIGHTER WEIGHT RECOIL SPRINGS HAVE A FASTER RECOIL TIME AND ALLOWS THE SHOOTER TO STAY ON TARGET AND RE-ADJUST TO THE TARGET FASTER AND EASIER 11 - 16 LB RECOIL SPRINGS ARE REDUCED POWER AMMUNITION LOADS17 - 18 LB RECOIL SPRINGS ARE GLOCK FACTORY WEIGHT RECOIL SPRINGS19 - 24 LB RECOIL SPRINGS ARE FOR HEAVY POWER AMMUNITION LOADS +p or +p+ THE CORRECT LOADS ARE NECESSARY TO MAKE SURE YOU DO NOT HAVE CYCLING ISSUES. Disclaimer - "GLOCK" is a federally registered trademark of Glock, Inc. or Glock Ges.m.b.H. GoTo GEAR has NO affiliation in any manner with, or otherwise endorsed by, Glock, Inc. or Glock Ges.m.b.H. The use of the word "GLOCK " on this page is merely to identify which firearm these parts or components are compatible with.