From the Manufacturer: Cover your crib mattress with this beautiful soft organic cotton crib fitted sheet.  Designed to mix and match, our organic crib sheets creates a comforting nest for baby's first dreams. Our soft 300 thread count organic cotton fitted sheets softens with every wash. Designed to fit securely and snuggly on any crib mattress with elastic pockets. Machine washable. Fits on any standard size crib mattress