Biological Sponge Filters Bio Filter operated by a airpump will mechanically clean biologically filter a aquarium. Bio Sponge Filters are a easy way to clean an aquarium, massive surface area allow bacteria to colonize and the sponge acts as a mechanical filter, just uses air to operate, so needs an air pump to operate. Weighted base and uplift tube included. Tip - When cleaning use the aquarium water to not kill off the friendly bacteria ? Biological Filters Driven By Air ? Simple To Use and Clean ? Cost Effective Filtration Small - 13.5cm Tall x 7.5cm Diameter, Including Uplift Tube Medium - 16cm Tall x 13cm Diameter, Including Uplift Tube Large - 16cm Tall x 15cm Diameter, Including Uplift Tube We sell many aquatic products online, check out our store!!! Terms and Conditions. We use all approved payment methods. 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 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.