Fitted rather than zippered
Same organic cotton fabric as the zippered encasement, cut as a fitted protector that goes on like a sheet. It covers the sleeping surface and the sides.
Choose the fitted version if the concern is allergen contact and comfort, and you want something a single person can change in under a minute. Choose the zippered encasement if you need a sealed six-sided barrier, which is what bed bug protection requires and what a fitted cover cannot give you.
Eleven sizes, from Twin 9 inch to California King 16 inch.