More room to play is what you get with this Twin over Twin Bunk Bed! Built-in sturdy metal that is solid, stable, and durable, this bed is designed shorter than the average bunk bed to fit smaller spaces and give your little one maximized space. This product comes with secured metal slats so no foundation is required. It also includes full-length guardrails and an integrated ladder to provide your child with the utmost safety. The bed fits two standard twin-size mattresses (sold separately) and the maximum mattress height for a top bunk is 6”.