The old mattress was covered with a mattress pad. I left the mattress pad around the old bed figuring which the Sensus mattress topper would be less likely to slip on the fabric pad. (The old mattress has an outer cover that is silky towards the contact.)
The Sensus mattress topper is a memory foam product manufactured by Foamex International Inc. Sensus foam is created in a vacuum chamber. Foamex uses a process called Variable Pressure Foaming, which, according to the manufacturer, means that this mattress topper will outperform other memory foam products.
Memory foam is designed to "remember" its original shape. Youve probably seen the commercials where someone presses their hand into a foam mattress, and after the hand is removed, the mattress springs back into its original shape. That is how the Sensus mattress topper works.
The Sensus mattress topper arrived via UPS on my doorstep in a cardboard carton. I very carefully opened the carton, not wanting to damage the contents inside with a knife. The packaging even states not to use a sharp object to open the carton.