Boyd Responda Flex® mattress is made with “open cell” memory foam, which promotes air flow and relieves pressure. Open cell foam contains billions of balloon-like cells with millions of tiny air passages in and around them where air can escape. Open cell foam’s breathable structure promotes the dissipation of heat, which keeps you cool and comfortable throughout the night. A traditional mattress or a closed cell memory foam mattress will “push back” when you lie down because the air in the sealed foam cells has nowhere to go. A BOYD open cell memory foam mattress will “melt” and spread the air pressure to adjoining cells to provide you with soothing comfort and contouring support.