Prowin M4 Hop-up Chamber - TDC Bracket Converter Kit (R-HOP/FLAT-HOP/ – Airtech Studios

Krytac M4 Hop-up Chamber - Modified R-HOP Arm – Airtech Studios

Hop Up and related parties

Prowin Hop-up Chamber- True Centering Unit (TCU) and Advanced Stabiliz – Airtech Studios

Airtech Studios R-Hop & Flat Hop Tension Nub (Hard Strength) for All AEG Hop Up Chamber

Krytac M4 Hop-up Chamber - Modified R-HOP Arm – Airtech Studios

Airtech Studios TDC Bracket Converter Kit For VFC M4/ SIG Sauer MCX Virtus Airsoft AEG (R-Hop /Flat-Hop / Maple Leaf MR) - eHobbyAsia

Prowin M4 Hop-up Chamber - TDC Bracket Converter Kit (R-HOP/FLAT-HOP/ – Airtech Studios

Prowin M4 Hop-up Chamber - Modified R-HOP Arm – Airtech Studios

Prowin M4 Hop-up Chamber - Modified R-HOP Arm – Airtech Studios