Watts bd2 s roof drain sump receiver. Part of the rd 200 series. B3 fc 2 deck opening 6 1 2 165 with sump receiver 8 203 b3 flg b3 dm 5 8 16 min 10 254 max underdeck clamp optional b3 body no hub shown 6 152 high self locking polyethylene dome flashing clamp gravel stop see chart a.