2 rail. I've shot 18s with rifle gas like how clean and accurate They can be. I am able to place extra money into performance elements then clone accurate sections like a ops brake and collar that I don't have a can for. KVC’s line of update choices for widespread https://kac-drop-in-rail42962.thenerdsblog.com/35128979/helping-the-others-realize-the-advantages-of-m4-ras