Primary Airsoft - HI-CAPA WE TECH HPA/M4 ADAPTER - AirsoftJunkiez.com
60D HPA M4 mag adapter for Hi-Capa series Blue
AVA Hi-Capa To MP5 HPA Adapter Available | Popular Airsoft: Welcome To The Airsoft World
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