With multiple layers of blended British wool and viscose, natural cotton, home-grown hemp and flax, mohair and sustainable Ecotex. The Perth has 12000 innovative springs; including dual action Cortec™ Revolution™ pocket springs, pressure relieving HD 4000 and HD 2500 Micro springs and flexible Posturfil pocket springs. With an in-house woven FR chemical free mattress cover and two rows of side stitching.