RBC flume were designed to be portable meters for measuring flow in small irrigation channels and field furrows. With the large variety of other flumes available to connect in-line with piping there has not been the push to develop other mounting / end connections for RBC flumes.
As a result, the only common mount or end connection is the wing wall.
Wing walls are flat plates that are attached to the flume to direct flow into or out of the flume from the larger channel that it's installed in.
Wing walls can be factory attached or shipped loosed for field installation as required.