This Aero Precision M4 Carbine includes one 20-round magazine, an arm brace, Magpul MOE pistol grip, a quad rail with rail covers, and a flash hider. It features a 1:7 twist barrel and also includes a CQD Forward Sling Mount and a Magpul AFG2 Angled Fore Grip. 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.