Designed specifically to accommodate trundle beds and top bunks, the Sealy Bella's Lullaby mattress offers guests a comfortable and supportive sleep surface. Utilizing a body-conforming layer of SealyFoam® on top of a 5" supportive foam core, this mattress responds to every curve, relieving uncomfortable pressure points to maintain a cozy sleep environment all through the night. Sealy Bella's Lullaby Full Mattress Set