Our crib does convert into a toddler bed, but there is no built-in rail. So again, being the nervous nelly that I am, I immediately thought of our Dock-A-Tot to keep her cozy and safe. The DockATot has been a lifesaver during our move! We used it for her to be able to nap on our bed a couple times as well and she has loved sleeping in it on her new bed and hasn’t fallen out once. visit dockatot.com to buy.