Paramount SDX2 004162223108 Light Grey Safety Drain for Concrete Pools, 2 Pack. SDX2 is a high flow suction outlet suitable for use as a wall fitting, or as a floor fitting when debris removal is not a concern. Available for concrete, vinyl and fiberglass pools, SDX2 performs at a very high flow rate while operating at one of the lowest velocity ratings in the industry. SDX2 boasts a flow rating of 188 gpm on the floor and 154 gpm on the wall.