The all-new, enhanced Serta Perfect Sleeper mattress provides even better pressure-relieving comfort and support, while maintaining a balanced sleeping temperature to help promote undisturbed sleep. Inside the Perfect Sleeper. CoolFeel Fabric luxurious, breathable cover with a coolto-the-touch sensation from technology that is plant-derived. HexCloud Gel Foam this exclusive gel foam features unique geometric cut outs that help relieve pain from pressure points. 825 Edition Custom Support Coil System In addition to providing curve-hugging support and minimizing the impact of your partnerâ€™s motions, this system of up to 825 individually wrapped coils features Sertaâ€™s BestEdge Foam Encasement technology â€“ an extra-deep foam rail to help reduce edge roll-off and extend the sleep surface.