Turn all your pillows into cool pillows. Extremely lightweight and airy, these covers stay cool without changing the feel of your pillow underneath. Ultralight and breathable construction combined with NASA-approved temperature regulating technology and moisture wicking fabric add up to a cooler night's rest. Technology: Outlast technology is a unique material capable of maintaining and regulating your temperature. As your skin temperature increases, the technology absorbs heat, then releases it when your skin temperature drops, so you sleep "just right." Materials Our premium lining fabric takes a proactive approach by employing active temperature control properties, versus other "cooling" bedding that is moisture-wicking and simply reactive. Tencel fibers offer a silky smooth feel and moisture wicking properties for the most comfortable night's sleep. Benefits Outlast materials improve comfort for: Anyone looking for a more comfortable night's sleep - they'll sleep cooler! Women experiencing menopause - hot flashes and resulting night sweats are reduced so they sleep cooler and drier. Thermally incompatible couples - individuals sleep at their own ideal temperature Research: We pass on everything we learn to our customers. From sleep studies to new technologies, we want to help you make informed decisions about your sleep. The thoughtfulness is in the details. It doesn't stop at thread count. It's the little things, the thoughtful details, that make our products the best available. Works Underneath Your Pillowcase: Designed to work even when used underneath your pillowcase Zippered Enclosure: Zippered enclosure transforms your existing pillows into performance "cooling" pillows Easy to Care For: Just throw it in your home washing machine Features: Extremely lightweight and airy Outlast technology is a unique material capable of maintaining and regulating your temperature Works Underneath Your Pillowcase Zippered Enclosure Easy to Care Specifications: Moisture Wicking Capabilities: Yes Slumber Cloud Outlast Performance Pillow Covers - King (Pack of 2)