The G42 Tungsten Guide Rod is designed with a slightly lighter spring to allow it to function with a wider range of ammo. This also makes it much easier to pull back the slide which has been a problem for many G42 shooters. Of course, the main advantage of the Tungsten Guide Rod is that the added weight helps reduce much of the felt recoil and also makes the gun function better, returning the slide more consistently and thereby improving overall accuracy!NoteGlockstore Heavy Tungsten Guide Rods weigh roughly 52-58 grams as compared to stock guide rods which weigh between 12-16 grams. DISCLAIMER: This product is not manufactured, authorized, endorsed, or warranted by GLOCK. GLOCK does not warrant or represent that this product is compatible with GLOCK pistols.