Bought not as a tool to increase windage for a wind instrument player but rather to increase my breathing efficiency. This involves training the diaphragm, (muscle), using resistive training. And for me, it works!
30 reps mornings and another 30 evening have slowly increased my breathing efficiency, I get deeper breaths and exchange the air more thoroughly in my lungs than I did before, which was more of a shallow kind of breathing. A bit strange to use at first but I soon got accustomed to it. Adding more resistance to my breathing with time was and is a gradual process, if I add too much I can really destroy my 30 reps. Take down and washing/rinsing is easy - not much of a chore at all actually.
Apparently this device is/or was prescribed by the British NHS. I’ve also read of relatively recent research that indicates it can help to reduce blood pressure over time. I can’t confirm or deny this but it does seem logical, at least to me, that this device would promote oxygen delivery to the brain and body. I have noticed firmer lower stomach muscles.
To learn how to use it I looked at some obviously old utoob videos from the UK. Looks as though this product has been marketed for quite a while. Anyway it does cost a bit for sure, probably overpriced for what it is, but I certainly don’t regret buying it. I could certainly imagine how it might benefit a player of wind instruments looking to increase their lung capacity and strength of breath.