Flintlock Workshop G3 QD Sling Adapter Kit For Classic Army G3 AEG
 
QD Sling Adapter: 3D printing PLA (Infill 100%) and Aluminum construction.
Classic Army G3 Rear Cap: Full Metal construction.
Fit for Tokyo Marui G3 / MC51 / G3SAS AEG and Classic Army G3 AEG Series.
QD Sling Swivel and the QD Rear Stock Pin Set are included.
NOT include the MC51 AEG in the photos.
It is durable enough for normal usage.
We cannot say it will not be unbreakable at extreme cases.