GBL Airsoft "The Captain" Metal Hop-up Unit for GHK M4

Features:

• Aluminum alloy construction
• Precision CNC machined
• Vivid anodized finish
• Improves accuracy and range. Provides enhanced performance over stock configuration
• Includes bucking

Compatibility: GHK M4 series gas blowback Airsoft rifles
Material: Aluminum alloy, rubber