Center Industries Magazines. I think it's aluminum with a plastic green follower. Okay is the same as nhmtg. Center Industries usgi 30 rd magazines. And other usgi. REDUCED from www.ar15.com 6p199 p/n 8448670 they also say. The enhanced performance magazine (epm) from center industries, cage code marked g9199. Brownells 30 round steel ar15 magazine with anti tilt followers.