Hew at eHobbyAsia:
An official Custom M4 GBB from G&P, based on the WA M4 GBB Rifle and WA internal parts combining with G&P metal upgrades, the G&P created a very unique M4 Custom. The G&P WOC Series – Sentry Type.
— WA Official Custom
— Based on WA M4 Series GBB Airsoft Rifle
— Full Metal Upgrade include internal & external parts