TEMPUR^® Material is memory foam, but no other memory foam is TEMPUR^® Material. Our formula has always remained secret. Fewer than 10 people in the world know how to make it, and they all work for us. Since we created the first memory foam mattress and pillow in 1991, TEMPUR^® Material has been at the heart of all our products. TEMPUR^® Material is viscoelastic, meaning both fluid and spring-like – achieved by billions of ultra-sensitive open cells existing between a solid and a liquid state. That’s the secret.