And make a suction sound. I bought these to walk to work in Portland. It is just right for my husband, who has had a partial amputation and has mobility issues. I love the ease of use and space saving potential of these. ANC works extremely well, and cancels most of the external ambient noise. On the bike they appear sturdy enough, well see. YOU ALWAYS HAVE TO WEAR THEM IN SLOWLY. The shoe felt so cheaply made. Definitely would buy a different set in the future. They don’t look as if they’ve been worn based on the heels.