After unpacking, allow 24 hours for the mattress to recover from its journey and reach its full size. The Ergolux Bonnell Spring Mattress is a medium to firm mattress that is good for pressure distribution. The mattress is 16cm thick and has a high density foam layer. The Bonnell spring coil system is a unique spring system that uses hourglass shaped springs to deliver a firmer fit than pocket spring systems. The Bonnell springs promote airflow and less heat retention so the mattress core is breathable and remains comfortably cool for a better night's sleep. The Ergolux 16cm Bonnell Spring Mattress is made with the finest selected materials for a great night's sleep.