I wanted an ear warmer that could be used for cycling and with headphones. They fit perfectly under the helmet in the neck; You must first put the helmet strap around your ears before putting them on. I was also able to wear them over Bluetooth headphones with no complaints as the headphones themselves are small; However, your mileage may vary in this regard, especially if your headphones protrude too much horizontally. They stay in place while cycling and feel warm enough. Although I've only tried them under 50, I have a feeling they'll be warm enough even in 30. At this point, you'll probably need even more headgear, especially if you're cycling or want to stay really warm.
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