2'' Ball Airstone 2'' (50mm) Round Air Stones, Value 2 Pk Diffuser High quality round air stone that will gives a rich micro bubbles of oxygen. Airflow dependent on depth of pond or aquarium and output of air pump. Fitting for all standard airlines. ? Value Two Pack Airstones ? 3/16th and 5/16th Fittings ? 2'' / 50mm Diameter We sell many aquatic products online, check out our store!!! Terms and Conditions. We use all approved methods for accepting payment. Sales Tax will be added to all shipments based regulations. We always try to combine purchases, please contact us directly for a personal service. You will be notified on the day that your goods have been dispatched via e-mail with tracking which is used on all purchases. Please note that if there are any problems, contact us first via e-mail giving full details of any problem along with your user ID. We use USPS and UPS as our chosen carriers shipments to Hawaii, Alaska Puerto Rico may incur surcharges, contact will be made to advise before shipment at which point the order can be cancelled if desired. Orders placed on Saturday/Sunday Public Holidays will be processed next working day. We pride ourselves on excellent feedback, if any part of the buying experience is not to your satisfaction, please contact us to rectify before leaving feedback. By committing to buy you are agreeing to the Terms Conditions stated above.