uxcell Aquarium Bubble Air Stone Air Tube Mineral, 4.6mm, Dark/Gray/Black Product Name : Aquarium Bubbles Air Stone; Suitable for : Fish Tank Aquarium; Tank Material : Mineral, Plastic; Air Stone Size(excluded connector) : 10.6 x 1.9cm/4.2" x 0.76"(D*H) Fit Air Tube : 4.6mm/0.18";Total Length : 13.8cm/5.4" Color : Dark Gray