AIM Sports Inc Complete AR Pistol Assembly Build Kit 5.56 NATO 10.5in Barrel M4 Profile Carbine 1-8 Twist 1/2x28 Thread 10M-LOK Free Float Handguard. 5" AR Pistol Everything you need to build your AR-Pistol except a stripped lower. Specifications for AIM Sports Inc Complete AR-15 5.56x45mm NATO 10.5in Pistol Upper Receiver w/ BCG LPK & Buffer tube Kit: Manufacturer: AIM Sports Inc Caliber: 5.56x45mm NATO Muzzle Device: A2 Flash Hider Finish: Type III Hardcoat Anodized Color: Black Gun Model: M4 Fabric/Material: 7075-T6 Aluminum Barrel Material: 4150 Chrome Moly Vanadium Features of AIM Sports Inc Complete AR-15 5.56x45mm NATO 10.5in Pistol Upper Receiver w/ BCG LPK & Buffer tube Kit UPPER: Mil-Spec Forged 7075-T6 Completely assembled upper receiver. Type III hard coat anodized for maximum durability. M4 Barrel Extensions BARREL: 10.5in 4150 Chrome Moly Vanadium Steel. 5.56 NATO Chamber. Nitride finished for protection against corrosion. BOLT CARRIER GROUP: Carrier body is 8620 steel and bolt is 9310 tool steel. Both are Nitride finished with excellent lubricity and corrosion resistance properties. Full Auto Profile BUFFER KIT: Features Pistol buffer tube 3.0 oz. buffer carbine buffer spring castle nut and end plate LOWER PARTS KIT: Complete Lower Parts kit includes Fire Control Group and A2 Grip. RAIL: 10in AIM Wraith M-LOK RailMid length gas tube and low profile gas block Package Contents: AIM Sports Inc Complete AR-15 5.56x45mm NATO 10.5in Pistol Upper Receiver w/ BCG LPK & Buffer tube Kit What firearm models does the manufacturer say AIM Sports Inc Complete AR-15 5.56x45mm NATO 10.5in Pistol Upper Receiver w/ BCG LPK & Buffer tube Kit is compatible with? The manufacturer suggests that AIM Sports Inc Complete AR-15 5.56x45mm NATO 10.5in Pistol Upper Receiver w/ BCG LPK & Buffer tube Kit is compatible with M4AIM Sports Inc AR5CUB9: Complete AR Pistol Assembly Build Kit 5.56 NATO 10.5in Barrel M4 Profile Carbine 1-8 Twist 1/2x28 Thread 10M-LOK Free Float Handguard A2 Birdcage Flash Hider Nitride Black