Hello . This is a Primary Weapons Sytems Mk. 107 Mod. 2M Diablo piston upper in .223 Wylde / .556 NATO cal . These are discontinued and were priced over $1,200 when they were available . In place of the original PWS CQB muzzle device it has a PWS Triad 556 muzzle device . I`m asking $800 for it . I also have an SBPDW pistol brace that go for $300 new . I`m asking $150 for it . I`ll sell the whole set up for $950 OBO . You wont beat that price . If you`re interested please contact Russ at 208-602-9390 . Thanks , Russ .