Check For ONLY For Co2 For Aquarium Co2 Line Tubing Regulator For Planted Tanks High-Quality StainleFeatures:This check for is only suitable for CO2 equipment stainless steel, it is not rusted and Easy to install and use, simple and convenient.Prevent water from entering carbon dioxide.Do not use with air pumps and air compressors.Specifications:Stainless steelColor: SilverSize: Length: app.4.7 for cm/1.85 in app.4 mm/0.16 inPackage Includes:1 x Aquarium check for Note 1. Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid.2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you!