This Colt M4A1 Carbine features a carbine quad rail with covers, a Knights Armament vertical foregrip, a removable rear sight, and a pinned and welded muzzle brake. Two 30-round magazines are included. Get the best bang for your buck when you get a Certified Used Firearm. When you see the Certified Used stamp on any of our firearms, you can be confident that you're getting exactly what you want - a gun only in very good to excellent condition and held to the highest quality standard. All Certified Used Guns come with a 'no questions asked' return policy.