Black Airline Tubing, Easily hide and blend into your hydroponics system, aquarium, terrarium Designed to fit all 3/16 standard outlets, including air pumps, check valves, filtration system, air stones, air flow control levers, and aquarium ornaments. This airline tubing is Black, flexible, reliable, and durable! Made for use in hydroponics systems, aquariums, terrariums! Safe: the material is non-toxic and harmless for health. 50 Feet Black Airline Tubing Aquarium Standard 3/16" Black Flexible Airline Tubing with Black Plastic Connectors for Fish Tank,Terrariums, and Hydroponics