Factory Armalite AR 10 T 243.Even though the lower says 308, I understand they put factory 243 uppers on these lowers. The package come with: Muzzle Brake Two 20 Round Mags two 10 Round Mags Sling Harris Bipod Brass Catcher Round Count-low from me, but I bought it used,supposed to be low from the seller I bought from. Twist- not fast twist,12 or 14 Hard Case $1600 plus shipping and insurance