Men's New Releases. Nike.com Bamboo Zip Romper Bootsberry Cowgirl. Premium fabric (220 GSM): Durable and soft; retains shape up to three times longer. Ultra soft and stretchy: 95% bamboo viscose and 5% spandex for exceptional comfort. Exclusive prints: Unique in house designs not found elsewhere. Two way zipper: Enables easy diaper changes and quick dressing. Tagless design: No scratchy labels for all day softness. Fold over mittens: Built in mitts help prevent accidental scratches. Convertible footies: Wear as a romper or fold into footed pajamas for extra warmth. Breathable and temperature regulating: Keeps little ones comfortable year round. Snug and safe fit: Designed for a secure, cozy feel. Easy care: Machine wash cold; tumble dry low. Chemical free: No flame retardants or harsh additives.