uxcell Aquarium Fish Tank Bubble Diffusers Maker Round Air Stones 40mm diameter aquarium fish tank ponds ceramic air stone diffusers it is suitable for filteration, ponds aquarium and hydroponic nutrient tanks! With the sands stone construction fish tank air stone can also be chemically cleaned without the risk of damaging the stone It produces fine bubbles making it efficient in the replacement of Oxygen in fish ponds, tanks or hydroponic systems. Size: 40mm(diameter) x 15mm(thick). Inlet Connector Size: approx. 3mm internal, 4mm external. Weight: 31g; package content: 1 x 40mm diameter aquarium air stone