This sleep mask has really helped me keep unwanted light out and improve my sleep. It’s knitted tightly in K1, P1 rib in 100% cotton for a snug fit.
Instructions include directions to fit your own head measurements.
Hand wash in cold water, and lay flat to dry. Best to make two, so as 1 can be in the wash and you’ll still have another while the first is drying, not to miss a good night’s sleep.