uxcell Aquarium Bubble Release Air Stone, 3.1-Inch, Indigo Blue Aquarium Air Stone; Color : Indigo Blue Material : Mineral Stone; Size : 8 x 1.5cm/3.9"x 0.6"(D*H) Fit Air Tube Dia : 5mm/0.2" Weight : 118g Package Contents : 1 x Aquarium Air Stone