The silentnight geltex affinity 1350 mattress is a firm and supportive addition to the geltex range with 6cm of geltex foam this mattress has air permeable foam with a unique open cell structure and elastic gel that allows for greater airflow to pass through and prevent overheating the 1350 zoned mirapocket spring system is the ultimate choice for a comfortable yet supportive sleep surface that contours to natural body shape weight is distributed evenly across the mattress with each spring