Aerofit Pro buy or not?

I’m thinking to buy the aerofit pro. I hope to get some stronger lungs, especially for the swim.

Anyone here that has possitive (or negative) experience with this “thing” ?

I doubt a bit cause it is expensive. Especially the monthly subscription holds me back. If it was one lifetime buy for full option use I won’t mind. But a montly payment is holds me back.

Any tip is welcome.

Regards,
DVR