All our uppers are carefully assembled and tested and ready to go out of the box. Every component is chosen to ensure a high quality upper is produced. Every upper is custom built to order and we go the extra mile to ensure the finished product is to your specifications. This 9mm upper starts with a Gibbz Arms G9 Non Reciprocating Side Charging Billet Aluminum receiver, mated to a White Label Armory 16 inch 9mm, 1:10 Twist, Nitride/Melonite treated barrel. The Gibbz Arms receiver is a proprietary patented receiver that has a non reciprocating side charging handle - handle stays forward during cycling. Side handle is on the opposite side of ejection port allowing the shooter to quickly charge or recharge the weapon without taking finger off the trigger and eye off the scope. White Label Armory is one of the major AR Parts manufacturer in the industry and they especially make great pistol caliber barrels. The Ghost Rail is a free floated system, M-LOK slots on all three sides, full length picatinny rail at the top, lightweight handguard. Barrel Nut is made out of solid steel to ensure a solid mounting system. Bolt Carrier Group is OPTIONAL. We offer a 9mm BCG from WL Armory, Properly Heat Treated, 8620 Single Piece Bolt, Nitrided. SPECIFICATIONS UPPER RECEIVER: Gibbz Arms G9 Non Reciprocating Side Charging Billet Aluminum Receiver with Gen 2 Handle, Type III Hardcoat Anodized Black BARREL: 16 inch, 9mm Caliber, 4150 Chrome Moly Vanadium Steel, 1:10 Twist, Nitride/Melonite Treated - made by White Label Armory HANDGUARD: 12 inch M-LOK Free Floated, Machined out of 6061 T6 Aluminum - made by Ghost Firearms GAS SYSTEM: Blowback System GAS BLOCK: Blowback System - No Gas Block Needed MUZZLE DEVICE: 9MM A2 Flash Hider and Crush Washer 100% MADE IN THE USA OPTIONAL: ADD a WL Armory 9mm Nitride BCG