【PREMIUM MATERIAL】: The Aquarium Co2 valve is made of high quality 304 stainless steel materials, very durable and sturdy. 【HIGH PERFORMANCE】: This 1 way check valve is anti leak and non backflow. Aquarium water valve is designed to prevent the aquarium from water flowing back because of maintenance, improve the service life of your carbon dioxide bottle. 【FOR CO2 EQUIPMENT】: The fish check valve is suitable for Aquarium CO2 system aquarium CO2 diffuser and NOT for air pumps. Perfect for the tube of inner diameter 4mm/0.16inch and outer diameter 6mm/0.24inch. 【EASY TO USE】: Our aquarium CO2 diffuser regulator is light in weight and compact in size, exquisite and small, smooth and flat surface, easy to clean. 【PACKAGE INCIUDE】: 1 Co2 valve only, other accessories is not included in the package. This CO2 bubble counter check valve is a great gift for family and friends who loves fishes breeding. Specification: Type: Aquarium Check Valve Material: Stainless Steel Size: 3.6cm/1.42inch Suitable for Air Inlet/Outlet Tube: Inner Diameter 4mm/0.16inch Outer Diameter 6mm/0.24inch Note: FOR CO2 SYSTEMS ONLY Feature: To stop water entering into CO2 Equipment Color: Silver Package Includes: 1 Aquarium Water Stop Check Valve Note: 1. Please allow slightly error due to manual measurement. 2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. 3. Wish you a wonderful online shopping!