Description Protect your patient or loved one from bed fall injuries with the Defined Perimeter Mattress Cover from Drive Medical. This easy-to-install surface features medium density foam roll bolsters to gently protect the user from rolling too far and risking falling off the bed, without the use of patient restraints. To promote easy transfers, this cover has an open gap in the mid-section. The breathable nylon material allows for use with either a foam or powered air surface. With the Defined Perimeter Mattress Cover, you will never have to worry about bed fall injuries again!