You’ve probably owned sheets that felt icy for a week and then quit. That cool touch was a chemical finish sprayed onto synthetic fabric, and it rinses away in the laundry.
Onuia sheets are 100% eucalyptus lyocell, and nothing else. No polyester, no blends, no coating. The breathability is the weave itself, so it can’t fade. Night three hundred feels like night one, and the fabric softens along the way instead of pilling.