The Ergolux Bonnell Spring Mattress is a medium to firm mattress that is good for pressure distribution. It is 16cm thick and has a high density foam layer. The Bonnell spring coil system is a spring system that uses springs that are hourglass shaped to deliver a firmer fit than pocket spring systems. Bonnel springs promote airflow and less heat retention so the mattress core is breathable and remains comfortably cool for a better night’s sleep. Whether you sleep in the middle of the mattress, toss and turn all night or share with a partner, Bonnell springs ensure you get the most supported sleep no matter where you lie.