[Lynn Eades]

Hi Euan, The riveted carriers have a special screw in cap that can be dis assembled and adjusted. It has a bellows arrangement.
Your set up with a commercial $6.00 cap is the best system. There is a lot of fafing around just to check the water level in a riveted carrier.
Kevin previously listed that he wants an elbow from the top, I want the diaphragm.
I will get a picture later up so you can see. Someone will have one, and not even know what it is.