@picartist Elaborating further. I think I may have just bought the guage, which does me little good without a connector. Monogram Medical makes the connector and I think most medical equipment people, like Vitality Medical, sell them together. I may have wasted money on two gauges, so we'll see. I do note that the one I did buy was with an Aerobika but they are usable on all three bika's I have. Now that I know how hard I should exhale air, I don't think I even need it any longer. I was exhaling extremely hard and it was not necessary.

@picartist I would not buy these because they do not have the connector to the Aerobika, I think I wasted my money. You need to buy them with another Aerobika because the connector is included.