CYMA Alloy Gear HOP-Up for M4/AR-15 AEGs

If you're looking for a robust and affordable replacement HOP-up for your M4 AEG, here you go! The CYMA Alloy Gear HOP-Up for M4/AR-15 AEGs is a replacement original parts set, including an alloy gear style HOP-up unit and a basic HOP-up bucking and nub, along with all springs, gears and cogs needed to build the unit.