Send a stream of air bubbles thru your aquarium bed with this high quality aquarium Airstone diffuser set. Simply attach to your air pump with standard airline tubing to create a decorative curtain of tiny bubbles that helps agitate and aerate your aquarium water. Great for freshwater, saltwater/reef/marine aquariums and hydroponic use Fits standard air line tubing. ? 4 Inch Diameter Stepped Fitting : 3/16" or 3/8" Standard ID airline tubing ? Sintered Long Lasting Stone ? Heavy Design Suitable For All Ponds And Large Aquariums ? Easy to clean and sanitize with soapy water We sell many aquatic products online, check out our store! Terms and Conditions. We all approved methods for accepting payment. Sales Tax will be added via, based on 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 canceled 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.