uxcell 1.1" Diameter Ball Shape Gray Air Bubble Release Stone for Aquarium Fish Tank Product Name: Aquarium Airstone Material: Mineral Stone & Plastic. Color: Gray & Black Outlet Diameter: 2.9mm / 0.11" Total Size: 29 x 43mm / 1.1" x 1.7" (D*H)) Weight: 24g. Package Contents: 1 x Aquarium Airstone