The newest evolution of our premier Guide Rod for the Walther PDP is finally here! The Gen 2 is ndesigned for compatibility between all 4-5 inch slide lengths. Originally developed for our friends at Modern Samurai Project, the guide rod was designed to allow a shooter to easily choose and swap the weight of the recoil spring. This stainless steel, captured guide rod ships with a 15lb ISMI recoil spring installed. Included in the package is a 13lb ISMI recoil spring for those that use a reduced power striker spring set-up or would like a slightly faster slide reciprocation. The retaining screw is slotted to allow for easy changes at the range during set-up. Once set-up, we highly recommend using Loctite 242 on the screw. Guide rod will accept all ISMI flatwire recoil springs designed for the Glock 17.