Flowmaster Commercial is a 4.75" removable top drain that features a double wall base and a snap in top (PVC). When installing this drain the tops are staggered past the joints making the joints very rigid. Because the Flowmaster Commercial Deck Drain tops are removable, this drain is easy to clean and the tops can be replaced if ever damaged. Flowmaster Commercial Deck Drain is used on many commercial swimming pools, patios and other areas where large amounts of water need to be removed.