We recommend using a flat mattress pad with the Quick Zip because it can be easily changed when changing your zip sheet. Our flat pad is luxurious and thick, and slightly stiff so that it won’t slide around, and comes with corner straps to give it even more staying power - though most customers find that they do not need them under QuickZip. The pad has a 100% cotton upper for breathability and is available in two styles - 100% cotton lower or with a waterproof polyurethane coating. (Crib is only available in the waterproof style) Shop Mattress Pads