9mm JG-9 upper receiver with M-LOK handguard, 9mm bolt carrier group, JG 9mm 4150 chrome moly vanadium steel barrel, JG ambidextrous charging handle and JG knurled 6 point directional compensator included NOTE This upper is machined for a gas tube although it is intended for blowback gas systems only Specifications for Jacob Grey Custom 9mm Complete Upper Assembly: Manufacturer: Jacob Grey Custom Color: Black Finish: Class III Type 2 Hard Coat Anodized Fabric/Material: 7075-T6 Barrel Twist Rate: 1-10 Handguard Type: Free-Float Attachment/Mount Type: M-LOK Gun Rail: M-LOK