G&G have shared details of their folding stock hinge for the RK74-T, RK74-E, or RK74-CQB:
Folding Stock Hinge
The folding stock hinge allows your RK74-T, RK74-E, or RK74-CQB to fold into a compact AK! Constructed out of heavy-duty aluminum, it is compatible with your favorite AEG buffer tube and stock combination. Designed solely for use with the G&G RK74 Series. Now available worldwide.
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