Marketlab Lumex Foam/Gel Mattress OverlayMarketlab Lumex Foam Gel Mattress Overlay Lumex Foam and Gel Mattress Overlays have set a new standard for pressure management. The unique combination of a non aqueous solid gel patterned layer inside a 2" solid foam base that's topped with 1" convoluted foam provides superior comfort at key pressure points for any body size or shape. Its also surprisingly light, making it easier on caregivers backs and arms.