Stern defense 9mm Ar15 complete upper. With mag well adapter for double stack Glock mags. 4" barrel, M-Lok hand guard. Works perfectly fine zero issues just dint need it anymore. Comes with magpul flip up sights. 

https://getstern.com/mag-ad9-w-mod4-4-m-lok-4-barrel-9mm-pistol-upper-kit/