Stegmeier Flowmaster 3 A/T FLO-AT3C-NB 10' Aluminum Deck Drain Top Cap Clear, without Base. Flowmaster 3 A/T is a removable top drain that features an Aluminum top. This product also features a double wall base and a snap in top. When installing this drain the tops are staggered past the joints making the joints very rigid. Because the Aluminum tops are removable this drain is easy to clean and the tops can be replaced if ever damaged. It is recommended that you drill and pin (3/8″ rebar) the base at 3 foot intervals to stabilize against any movement in the concrete slab. Stegmeier LLC offers a fiberglass Drain Dowel for this purpose. Flowmaster 3 A/T is used on many commercial swimming pools and indoor pedestrian traffic areas.