AIR AND WATER BEDS- are mattresses that use filled chambers to provide support. These then can be covered with a topper(which is like the spring mattress's upholstery layer. These can have separate chambers allowing each person to set their own comfort and support level. Note: Because air and water can only displace not eat energy the setting that is comfortable may not be the setting that is correct for support. They also have had reports of mold growth. This is a maintenance problem the casings need to be cleaned periodically.
FIBERS-There are many types of fibers used in bedding both natural and synthetic. These are generally used to lesson body impression and control temperature, not to add comfort. As the fibers were crushed they would loose their comfort making ability Grade of material is a factor( ex. Cashmere is better than plain wool.
BOX SPRINGS-There are four major styles. Wood commonly called a foundation. Semi Flex is the same as a foundation using metal struts Torsion bar a movable box spring that added shock absorbing value to the box &Spring this used to be the best but now is the worst. It has the most shock absorbing value and used to help with body shaping.Today with one sided beds the innerspring generally sits on a block of high density foam.The more the box spring can flex the quicker this foam block will wear causing deeper body impressions and the illusion of sagging. In addition it will increase the bounce or motion transfer. Box springs are usually in two pieces for a king bed enabling them to moved into smaller spaces. Splits as these are called are available for queen and full sized beds.
You will find terms and conditions on Mattress Information home page