This is the same system as WOW saddles use. You can buy the pump (also supplied with Korrector pads) but its best to have it fitted by a WOW fitter initially...
I got my saddle converted to flair a few months ago. wish i'd done it sooner. my id x tb has always been difficult to get a saddle to fit but since using flair she has been going so much better.
doesn't suit all horses but the theory behind it is pretty sound. getting first adjustment soon so not sure of cost.
Very good. An alteration/ fitting with the air costs about £25-35 depending where you live, or you can buy a special pump and do it your self, but it's probebly best to get a fitter to do it if you are new to the system.