The Aladdin 16506 R Replacement Pool and Spa Filter is designed to replace the filters in pools using the Watkins 65, the Unicel C-8465 or the Pleatco PWK65 filters. This compatible filter made by Filbur is capable of cleaning a pool or spa area of 65 feet. This Aladdin 16506 Replacement Pool and Spa Cartridge is designed with a pleated media for filtering unwanted contaminates from your pool or spa. It is constructed with durable materials to avoid ripping and tearing. The top and bottom holes are three inches in diameter.