Style, comfort, and functionality come together beautifully with the Aden + Anais 100% cotton muslin fitted crib sheet. Wonderfully soft and the ultimate in breathability, cotton muslin is the ideal fabric to keep baby warm in winter and cool in summer. So every night will be dream like for baby and you. Available in single packs. Breathable: open-weave allows liberal airflow. Year-round comfort: warm in winter, cool in summer. Tailored fit: fits standard crib mattress (50" x 28") Machine washable: softer with every wash.