The Spring Memory mattress has 50 mm Memory Foam supported by a bonnell Spring system. The mattress is very comfortable as the Memory Foam follows the outline of your body. The bonnell Springs help in providing bouncy comfort as you get your much-needed rest. The encap foam above the Springs aids in preventing rolling off the mattress.. . The Spring Memory is an Orthopaedic mattress crafted with sanitised materials which make it hypoallergenic and Anti-Dust Mite. If you have allergies or asthma, this mattress is perfect for you.. . This mattress conforms to all British fire regulations for your peace of mind..