25' Aquarium Air Line Tubing for Fish Tank - High-Quality Flexible Oxygen Tubing for Aquariums, Air Pumps, and Bubbles - Perfect for Freshwater & Saltwater Fish Tanks, Hydroponics, and Pond Aeration

It is an Air line tubing and does the job -priced well too. It is well packaged and not tight enough for the line to have dents which cause the line to deteriorate faster. The size is convenient because many of us who start in the aquarium hobby, start with one and continue having other aquariums -so just cut the size needed and store the rest away for the next project. I have used these for drip acclimatization of fish from the fish store, water changes, as a bubbler for raising Brine Shrimp, and even inside of bottles where the head of a syringe inserts right into the air line tubing allowing measured medication or fertilizers into the tank without any liquid entering the syringe which avoid cross contact/contamination.