As answer, I have behind/on top of the ear models, with the tube that goes to the in-the-ear tiny speaker. On my current model from HearUSA the rubber piece that keeps the speaker in the canal is sealed and does not have openings. I’m told this provides better sound quality and control. I have had Costco units where the rubber piece was perforated.
I’ve only worn my Costco units once while cycling, had wind noise so stopped using them. I suppose I could get them programmed differently, will have to ask.
My loss is not cycling related but is genetic, as my mother, as well as older sister and brother all wear/wore aids at earlier ages, so not a result of aging. As well I’ve worked 44 years in the theater business and have been subject too much loud noise while wearing amplified communications headsets, so have work related loss from that. In short I can’t hear sit.