Kaymed AtlasMighty Bed mattresses always deliver a firmer yet sumptuous feel, and are guaranteed to stay that way for many years. *Sleep both sides to extend mattress life and performance - please turn and rotate regularly *Mighty pocket sprung mattress technology Mattress Dimensions. *Single - 90cm w x 190cm lx 30cm d *Small Double - 120 w x 190 l x 30cm d *Double - 135cm w x 190cm lx 30cm d *King - 150cm w x 200cm lx 30cm d *Superking - 180cm w x 200cm lx 30cm d Important Information:. Please note that pocket sprung mattresses must not be used with a base for which they are not designed. Slats on a bed frame should be no less than 70mm apart, to ensure the mattress receives adequate support. Failure to use an adequate base could invalidate the warranty from the manufacturer. Please check with us for more details.