Nest by Ru9 mattress is made up of 2 layers of foam: The top layer of Ru9 Contour Foam provides full body support throughout the night, combined with Ru9 Support Foam underneath, which is very durable and keeps the mattress from sinking for many years. . In addition, 2 layers of foam are covered with a layer of fireproof cotton, making your home safer in case of emergency. The Tencel mattress cover is breathable, easy to disassemble, both to help you sleep more cool, and convenient for cleaning, ensuring the health of the user.