Uxcell 2-Piece Aquarium Port Balls Air Stones, 5mm, Green Product Name : Aquarium Air Stone; Suitable for : Aquarium Design : Ball; Material : Mineral, Plastic Ball Diameter : 2.5cm/1"; Air Tube Port Outer Diameter : 5mm/0.2" Color : Green; Net Weight : 28g Package : 2 x Air Stone