ATH-M50X Headband Pad Replacement [Build notes in the comments] : r/headphones
Ath M50x Replacement Headband | Ath M50x Headband Cover | Cover Headband Ath M50 - Protective Sleeve - Aliexpress
Amazon.com: TRANSTEK ATH M50X Headband Cover - Also Compatible with ATH M50, M40X, M40, Cloud 2, Cloud Pro, Cloud Alpha, G PRO X, HS50, HS60, HS70 Headphones (Black) : Electronics