G&P M4A1 10inch Aluminum Outer Barrel (Black) EBB you'll see the hop up

you'll see the hop up unit

DYTAC Water Transfer M4 Metal Receiver for AEG (Reape Black)  Aluminum Die Castng Construction  Suitable for M4 / M16 Series Airsoft Electric Gun AEG Rifle  Package Include Dust Cover

Aluminum and Acetal  Battery Compartment able to hold TWO CR123A Batteries  O-Ring Sealed provide water resistance functionally  Quick Detach Lever Design  Fit all 20mm Picatinny RIS Rail

Use WE SMG-8 Magazine

G&P M4A1 10inch Aluminum Outer Barrel (Black) EBB you'll see the hop upReinforced Aluminum Constructed One Piece Outer Barrel Suitable for M4A1 Series Airsoft Electric Gun AEG Rifle Fit for G&P Front Set RAS series to install with Tokyo Marui Barrel tip end has Clockwise 14mm Thread Super rigid construction for high end upgrade user SKU GP COP005B Item Weight (gram) 200 Major Color Black Length 250mm Adaptive End 14mm Clockwise Built Material Aluminum Manufacturer G&P