Penn Plax (STD8) Silicone Aquarium Airline Tubing, 8-Feet This aquarium tubing has many benefits one is that its versatile to fit any standard aquarium gang valves Silicon Tubing measures .50"D x 3"W x 7"W and it has an aqua colored tint to blend into aquarium setting. Features flexible silicone that will never crack, harden, or kink.