Cover: With a hand tufted luxury damask cover with quilted border and air vents. Sprung mattress: Get an orthopaedic Bonnell spring unit mattress! Construction: With a 12.5G Bonnell spring unit for fantastic support. Firmness: Medium - ideal for those who like to sleep on their side. Size: Choose single (3ft), double (4ft6) or king (5ft). Orthopaedic Bonnell Spring Unit Mattress | Living Social