We purchased this topper to go on top of existing memory foam mattress because we stayed at a friends house who had one and it was fantastic. We have a king size bed and we are both almost 50. Buy Linenspa 2 Inch Gel Infused Memory Foam Mattress Topper, Twin: Mattress Toppers – Amazon.com FREE DELIVERY possible on eligible purchases Memory Foam Mattress Toppers offer a layer of supportive comfort to your existing mattress. Toppers are a simple and cheap alternative to a new memory foam mattress, enabling you to experience the pressure-alleviating benefits at a budget price. .