The Old Bed is a variant of the normal bed and is used by prisoners to satisfy their sleep needs. It is cheap and reduces the room grade by 1 point, but better than Foam Mattress. The negative modifier can be used to your advantage to act as a balancing factor for your gradings between security categories.
It appears to be a metal grate suspended onto the wall, with the only thing on it being a piece of old foam.
See bed for more information.