@zak Had good luck with this $23 generic case. https://www.amazon.com/dp/B08VN94QNH

Absolutely love how compact the case is, though be aware of these 3 issues:
1) Have to adjust headphones before I put them in case.
2) No great way to attach to a backpack.
3) Had to let the case air out for a few days after receipt due to manufacturing smells.