Standard 3/16 inch diameter tubing is great for all your aquarium airline needs. Safe for salt and freshwater aquatic environments. This airline tubing is built to last and withstand wear and tear. It is also resistant to kinking. Great for use with aquarium ornaments or bubblers and many filters. Alegi Standard 3/16" Flexible Airline Tubing with Connectors for Aquariums, Terrariums and Hydroponics