SR4 FALCON Magazine Adapter for M4/M16 replicas - shop Gunfire
Airsoft Evike.com - SMG mags or M4 mags? You don't need to choose with the Valken ASL! Comes with the SMG mag adapter so you can interchange = Best of both worlds!
Valken SMG Magazine Adapter for M4 Platforms
MP5 AR, M4 Adapter & Stock Complete - HKPARTS
Tactical M4 Speed Loader Inventory AK Vector Adapter for AK G36 MP5 Holster Magazine Accessories|Scope Mounts & Accessories| - AliExpress
ARP-9? Got my mag adapter today : r/airsoft
AP10 MP5 Mag Bracket for APS UAR | Popular Airsoft: Welcome To The Airsoft World