This is a Magpul Industries Adapter known as the MS1, model MAG516-GRY.
Combine with the MS1 Sling and Paraclip(TM) to provide two to one-point convertibility. Melonite(TM) finished steel and reinforced polymer hardware combined with custom snag-free" high durability 1-1/4" webbing. Made in U.S.A.
Features:
Light weight yet durable hardware
Provides weapon quick-release capabilities
Extreme resistance to wear and corrosion
