If you never want to replace a gas tube get this - V Seven Extreme Environment Gas Tube

Most ar15 owners will likely never need to replace a regular gas tube. But if you want one that you guarantee that then this is the one for you.
If running full auto, binary trigger, etc. this also would be a good gas tube but would need to keep an eye on barrel temperature to make sure you don't over heat the barrel in too short period of time since this gas tube likely won't be the first thing to malfunction like it was designed to. If you can afford to dump magazine after magazine with ammo prices as high as they are right now I mean.
It's thicker than the average gas tube leading up to where it enters the upper receiver so will not be compatible with all barrel nuts for all hand guards without maybe some modifications to the barrel and/or hand guard. It fit Midwest industries SP rail and aero precisions enhanced gen 2 hand guard without any modifications.