The clever design of Luxemburg 3n1 Crib will carry your baby well into the toddler years. A five-position adjustable stabilizer bar allows you to place the mattress board at the correct height for each stage in your childs life. For an infant, the mattress is placed at the highest position, making it easy to place him in the crib. As he grows, the mattress can be lowered to prevent him from climbing out. When the time comes, the crib transforms into a day/night toddler bed. The crib mattress is sold separately.