Our cribs are convertible and are built solid,safe and sturdy and designed to grow with your child. Cribs are designed with stationary sides; no moving parts for safety. Cribs are all standard and fit standard size crib mattress which are sold separately. After your nursery needs have been met, our cribs transition into a toddler bed, a daybed that becomes a casual napping spot for any room in the house. Our high back cribs transition into full size beds with a headboard and footboard. These three or four modes allow your crib to convert and grow with your child. All of our traditional, convertible cribs offer a 3 position, metal or wood mattress support system. When your baby is first born, you will want to keep your mattress at the top or highest position. As your baby starts standing, you will need to lower the heights. As your baby starts standing, you will know it is time to lower the heights. By the time your baby begins to pull up, usually around 5-6 months, the mattress height should be at its lowest point. Another name for this type of 3-in-1 crib is a traditional crib. Instead of having a high back, the traditional crib has two high side rails where both the back and the front gates can be lowered (35”). The fully convertible crib will take you through the teen years. When purchasing a convertible crib, it is strongly recommended to purchase the toddler or full size bed conversion kits at the same time.