This is a Midwest Industries lower with a 7.5-inch, I believe, Geissele automatics barrel with a brand new BCG and buffer spring and it comes with an older BCG and a heavier buffer spring and a h3 buffer weight on the side. I got a h1 in it right now with a frt and a 3-way safety to select semi and full auto, and a Sig Romeo red dot (text REDACTED/p>