Click to expand Tap to zoom Ace1Arms CNC M4/M16 Hop-Up Chamber Unit by Ace1Arms Out of Stock $34.99 SKU ACE-HOP-M4-CNC 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Out of Stock Features 7075 aviation Aluminum CNC Construction Surface treatment: Hard anodic oxidation Design to replace the original Hop-up chamber for an optimized option Suitable for the majority of TM style M4 AEG