Rest Evercool King Cool Grey Pillowcase pairs a crisp percale weave with a performance fabric blend to keep Eastern King pillows cool and dry through the night. The construction uses 7% ionic silver nylon, 80% nylon and 13% spandex to wick moisture, provide antimicrobial benefits, and give enough stretch for a snug fit. It is machine washable for easy care so you can maintain a fresh sleep surface without special treatment.