Viscoelastic foam was invented by NASA in 1966 and is commonly known as memory foam. This type of foam is made of petroleum-based polyurethane and other chemicals and is now being used in mattresses, pillows, and other bedding products.
Memory foam mattresses relieve pressure points and reduce back pain and soreness. They are effective in preventing certain sleep disorders such as sleep apnea, insomnia, narcolepsy, and restless leg syndrome.
Products that are manufactured with natural human or synthetic hair and used to cover baldness or the existing hair on the head are called wigs or extensions. The hair wigs also are used as partial head coverings to cover areas with less or no hair as well as for beautification purposes. Wigs are designed to be worn over the head using full or frontal lace and filaments. The hair extensions are strands of hair that are added to the existing hair or worn on the scalp to increase the length or volume of hair.