Centennial defense spring - Centennial Defense Systems MOD4 Stainless Steel Guide Rod Assembly for Gen 1-3 Glock 17 w/Button Head Allen Screw

Easily installed works flawlessly the orange tip actually looks pretty cool. Changing the spring helped a lot cause I put a custom Zev slide on my Glock. I needed to lower the spring weight a bit so I bought a couple of different options ended up going with the 13 pound and it worked flawlessly really appreciate the ease of use and installation.