uxcell Aquarium Dark Gray Round Mineral Bubble Air Stone 150mmx18mm Product Name : Aquarium Bubble Air Stone;Suitable for : Fish Tank, Aquarium Main Material : Mineral;Air Stone Size(excluded connector) : 150 x 18mm/ 5.9" x 0.7"(D*T) Connector Size : 2.5 x 5mm/ 0.09" x 0.19"(Inner Dia*OD);Total Length : 17.5cm/ 6.8" Color : Dark Gray;Net Weight : 309g Please soak the air stone in water for at least 15 minutes before use.