Ten years ago I bought an expensive RH chair and it was a good purchase.

This kind of chair have a comfortable built-in lumbar support which one inflates by means of a squeezable hand pump.

Unfortunately, some kinds of plastics deteriorate under time and eventually made the pump unusable (right); and the plastic valve (left) which is supposed to keep air from coming out of the lumbar support was not airtight.

Since I have plenty of spare bike valves I tried to replace the original valve with a hopefully tighter bike valve; this would enable me to inflate once and for all the lumbar support.

I had to add another rubber ring to the valve, as the image below shows. This because since this kind of valve lets air in from the sides of the cylinder (pointed in both images by a red arrow), and the chair's rubber tube through which the air flow adheres very tight to the bike valve, I had to diminish the adherence near the air sockets.

This partially blocks the air inflow: you can feel it when pumping, but it is sufficient to inflate it in less than five seconds. It is just that one does not expect such a resistance, but it is not an hinder per se.

The disadvantages are that right now one needs

• some other mean, e.g. a small piece of wire such as that a staple is made of, to deinflate the lumbar support.
• a bike pump to inflate the lumbar support.

Yet the chair's lumbar support is now really airtight, which had never been since I bought it. And I do have a staple and a bicycle pump near my desk, even before I came to think of this solution. I am satisfied.