Attachment to the back of your smartphone (or smartphone case) to wrap your headphone

Phokus

Lifer
Nov 20, 1999
22,994
779
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I think i've seen something where you have this adhesive accessory that you stick on the back of your smart phone or your case that has a thing you can use to wrap your headpones around. Does anyone know what these are called or have a link? Thanks!