Rookie Humans fitted crib sheets fit US standard crib mattresses 52 x 28 inches. Made with soft 100% cotton sateen, 230 thread count. OEKO-TEX® certified and crafted without harmful chemicals. Lab tested to last, compliant with US regulations. Premium printing method ensures colorful, sharp details that remain vibrant. Beautifully packaged to make a unique baby shower gift. New Parents and Grandparents' nurseries will love having a few of these sheets!