FPR CNC Steel STI Route Type 31rds Gas Magazine (150mm) for Marui Hi-Capa 5.1 GBB Capacity-(rds)_520 you need the USB-Link which

you need the USB-Link which is not included in this kit

ASTER Module with BASIC firmware edition (Rear wired)

Hop-up can alternatively be used with two larger setting screws at the cost of quick-change keeping hop setting ability

CAW SAA 2nd Cavalry STD Heavyweight Black Model Gun

With this design

FPR CNC Steel STI Route Type 31rds Gas Magazine (150mm) for Marui Hi-Capa 5.1 GBB Capacity-(rds)_520 you need the USB-Link whichFPR CNC Steel STI Route Type 31rds Gas Magazine (150mm) for Marui Hi Capa 5. 1 GBB CNC Steel Construction 31 Rounds Loading Capacity Come With Protective Magazine Base Suitable For Tokyo Marui Hi Capa 5. 1 Series Airsoft Gs Blow Back GBB Pistol