4 inch Sump Bottom Drain for Koi Pond Water Garden 4 inch outlet Sump Bottom Drain comes with adjustable lid and liner collar. Complete with screws. A bottom drain is used on a pond which has a gravity fed filter system. Water and pond waste leave the pond via the bottom drain, travel along a length of pipe, and into the pond?s filter. Bottom drains are located on the pond floor, and should be positioned in the deeper areas of the pond. ? Fits Standard 4" Pipework ? Adjustable Lid and Liner Collar ? Solid Plastic, Complete with Screws 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 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 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.