Aqualine QCK-075 - 3/4" Replacement Quick coupling key: Key threads into top of quick-coupling valve to provide water access. Durable brass construction. Key is inserted into quick coupler valve to allow water flow. Threaded for 1" hoses and is internally threaded for impact sprinklers. For use with the 1" water hose. *You can also add a brass swivel elbow for 360-degree, kink-free watering with your hose.