The Fly High 1100 (W719-EXV) has fill/drain plugs on both ends while the W719 has a fill/drain on one end only. I got the EXV and connected it to a Fly High 11004 375# tube sac under the port side seats. That was the only way I could get it to fill and drain both bags using the pump. Prior to that I used the W719 with one fill/drain valve and connected the vent to the fill on the tube sac. That configuration filled fine but had to be manually drained.