PewClub Entertainment finds it fun using the Tokyo Marui MTR-16 GBB that uses HPA as power source with the AirTac HPA Adapter. This HPA adapter is a shortened magazine and HPA adapter for the Tokyo Marui GBB MWS from the ground up. The outcome is an extremely lightweight configuration that offers a more enjoyable and cost-effective alternative to purchasing gas magazines. It requires a donor magazine for the feed lips, exhaust valve, gas route, and valve knocker.