Purely 100% cotton cover: waffle grid pure cotton cover that brings extreme breathability, more importantly the sensitive skin care. Designed for mini crib: 38x24 inch standard size that perfectly fits for the mini cribs. (Please measure your mini crib size before purchase) Premium high density foam: 3 inch medium firm support foam that minimizes the risk of suffocation. (Please note: allow at least 48hrs to let the foam fully expand. It will be taking a longer time in cold temperature. Ventilating will accelerate this process) Steady & Safety secured: edge-reinforcement design for every single corner and sideline, all-roundly secure safety of sleep. Durable and reliable: CertiPUR-USA foam certified. For any further questions or dissatisfaction, We will be always offering you a better and satisfied solution. Mini crib mattress