Active Support Foam – Align that spine and feel fine.
A high quality, tried and true durable support foam that holds its physical properties over time and is designed to correctly align your spine for an ideal sleep position.  The support layer in most foam mattresses is most likely the thickest and comprises most of the mattress.  Therefore, it is imperative to use high quality foam here.  If a mattress sags or begins to ‘hammock’ more than likely it is because this layer of foam has failed.  Ironically, since this is most of the mattress, companies can save money by using inferior low-density foam here, which will not be evident at first but will wear quickly in 2-3 years. You will not find any cheap, generic yellow foam in the Aslan mattress.