1. Sleeve locking mechanism is engaged by rotating sleeve after connection.It prevents accidental disconnection when,the coupling is dragged along the ground. 2. Sleeve mechanism is designed to help prevent dirt from entering the intermal mechanism and thus causing faulty operation when connecting or disconnecting.the sleeve covers the retaining ring and also in corporates a dust seal in the spring. 3. Steel construction,Zinc plated with yellow chromate finish.Hardened nipples and sleeves and solid barstock construction for maximum resistance to damage from hydraulic and mechanical shock. 4. This Anti-Blowout Nitrile/PTFE bonded seal is designed to prevent blow-out or damage during severe service conditions. 5. Durable ball-locking mechanism assures reliable connections, every time. A large number of locking balls distributes the work load evenly while providing alignment and swiveling action to reduce hose torque and prolong hose life.CAUTION:These products are not to be used as swivels.Rotation under pressure will result in excessive and premature wear. 6. This series couplings employ flush valving when connecting or that only small amounts of fluid can be lost during disconnection or air inclusion during reconnection. 7. This series conforms to standard of ISO16028.