A neighbor of mine has a washing machine drain line hook-up that is unlike anything I've ever seen. There is a "T" shaped PVC fitting at the wall that I'll call a "gizmo" for now. The bottom leg of the T is hard plumbed into the wall drain pipe (in other words it is a threaded fitting screwed onto the drain wall pipe. One of the top T legs has the drain hose from the washing machine clamped onto it with a hose clamp. The other top T leg is kind of like a one way air check valve that will let air in when the washer is draining but is supposed to shut if water doesn't flow down drain pipe quick enough (four small holes with a rubber seal on the back side). The problem is the seal is not sealing completely and the gizmo is leaking. Does anyone know what this is called and/or where I could purchase a new one? Also, we tried eliminating the gizmo and just hooking the drain line into the wall drain pipe but it overflowed right away when the washer went into it's drain cycle. The leak from the gizmo is minor compared to when we eliminated it. I'll attach a couple of pics of the gizmo. Anyone's help would be greatly appreciated. Tried to attach pics but just wouldn't upload properly.