40mm Visco-Elastic Memory Foam 20mm Reflex Foam 55kg/m&sup 3; Density Memory Foam Trizone System Memory Foam Layer Micro Quilted Medium Tension Airsprungs Trizone is from the memory master selection & is designed to give extra support & firmness. The Trizone is designed with three phases with the first & last eight rows of springs offering normal support, & the centre springs offering extra support in the lumber region. On top of this is a layer of memory foam which moulds to the shape of the bodys contours to give a pleasant & comfortable nights sleep. The mattress by Airsprung has a micro quilted finish & has a medium tension. Suitable for a wide range of divan bases, or bedsteads that are available on our website. Please note as this is a memory foam mattress, you may expect a slight odour within the first week of use. This is due to the fire retardant spray used on the memory foam.