GhostBed claims that the latex foam layer in its Classic mattress draws heat away from the body and keeps sleepers cool. Cooling mattresses also feature materials that promote airflow through the mattress or absorb heat from the body. Additionally, they include special foam layers or copper- or gel-infused top layers throughout the mattress. A person can also try other methods of keeping cool during sleep if their mattress does not keep them cool enough. For example, they can use cotton sheets, air conditioning, or fans. The National Sleep Foundation states that keeping the room cool can improve sleep quality and that a temperature of 60–67ºF (15.5–19.4ºC) can help people fall asleep.