The Oxford Baby Twilight Lightweight Foam Standard Crib & Toddler Mattress is a high-quality, durable crib-to-toddler mattress with a 5 in. bonded polyester core. Your infant or toddler can sleep on either side of this semi-firm polyester core mattress, making for a more restful night's sleep. The mattress is lightweight (7 lbs.) and includes a nylon, stain resistant waterproof mattress cover for easy cleaning. Mattress measures 52 in. L x 27.5 in. W x 5 in. H and fits standard sized cribs and toddler beds.