This True Precision recoil spring tuning kit is built for the Glock 19 Gen 4, Gen 5 and V and their aftermarket copies, and it includes the adapter bushing those generations need. The kit is also compatible with Glock 19 Gen 1-6 pistols. Use it to tune cycling on a compensated or suppressed Glock 19, a lighter or heavier slide, or a change in ammo. The springs are high-strength chrome silicon, rated for more than 20,000 compressions each. A billet-machined stainless steel guide rod (non-captured) is included, so you can swap spring weights without buying a new rod assembly. Features: Designed for Glock 19 Gen 1-6 models and aftermarket copies Adapter bushing for Gen 4, Gen 5 and V included High-strength chrome-silicon springs Stainless steel, billet-machined non-captured guide rod Includes 11 lb, 13 lb, 15 lb, 18 lb, 20 lb and 22 lb springs 100% made in the USA Start with the spring weight closest to your current setup and adjust one step at a time. Function-check with your carry ammo after each change, and confirm reliable lock-back on an empty magazine before you carry or compete with it. DISCLAIMER: "GLOCK" is a federally registered trademark of GLOCK, Inc. and is one of many trademarks owned by GLOCK, Inc. and GLOCK Ges.m.b.H. Neither 3CR Tactical nor this site are affiliated in any manner with, or otherwise endorsed by, GLOCK, Inc. or GLOCK Ges.m.b.H. The use of "GLOCK" on this page is merely to advertise the sale of GLOCK pistols, parts, or components. For additional genuine GLOCK, Inc. and GLOCK Ges.m.b.H products and parts visit www.glock.com.