Uxcell 6-Piece Sintered Mineral Bubbles Fish Tank Airstones Set, Assorted Size Aquarium Air Stone; Color : Blue, Gray Material : Mineral Stone; Max. Air Stone Size(excluded connector) : 4.5 x 2.3cm/1.7" x 0.9"(D*H) Min. Air Stone Size(excluded connector) : 2.5 x 1.5cm/0.9" x 0.5"(D*H); Fit Air Tube : 5mm/0.19", 4.1mm/0.16" Weight : 98g Package Contents : 6 x Aquarium Air Stone