I know a lot of people hate the Primary Airsoft adapters, but when it's 110° outside, a light kit is a life saver. Also a great first step into HPA : r/airsoft
STL file HiCapa to M4 - HPA Adapter・3D printing model to download・Cults
STL file HI-CAPA to M4 HPA ADAPTER・Design to download and 3D print・Cults
HI-CAPA adapter - M4
Primary Airsoft HPA M4 Adapter - YouTube
Hi capa HPA and M4 adapter (NUEV9ECAF) by PrimaryAirsoft
Hi-Capa Shotgun Shell HPA Adapter | Tapp Airsoft
Primary Airsoft - HI-CAPA WE TECH HPA/M4 ADAPTER - AirsoftJunkiez.com
Primary Airsoft - HI-CAPA WE TECH HPA/M4 ADAPTER - AirsoftJunkiez.com