This piece allows the setting of the S-Bend Tube height and position. When in the desired position on the tube it is tightened with a 5/32 inch Allen Key. When the S-Bend Tube slips into the Releasable Mounting Clamp the Index Collar rests on the clamp (preventing the tube from sliding down any further). A positioning notch on the Index Collar fits the positioning pin on the clamp so that the desired S-Bend Tube position can be regained after removal and replacement.