Modify - Bore up Cylinder for M4A1, XM177, SIG551 AEGs - GU-01-03
MOD-GU-01-03Modify Bore Up Type 2 Cylinder for M4 Series AEG
Stainless construction with ribbed walls and smooth finish
For Modify/Systema Bore-Up series use
Please use with M120 spring or higher
Made in Taiwan