This 4 pack of black female adapter fittings is designed to connect the APEX dos pump to standard 1/4 inch RODI tubing, making it a push fit for easy and secure connections. Each fitting features a tapered design that requires cutting on the DOS head to ensure proper installation. It is recommended to use Teflon paste between the DOS head and the JG push lock fitting to guarantee a reliable seal, enhancing the durability of your aquarium dosing system. Ideal for reef aquarists who are using Neptune Systems DOS pumps as part of their water chemistry management setup, these adapters streamline dosing processes and improve overall system reliability.