Thank you for viewing! These hair ties can be used by adults, babies, and kids! The rubber band can be replaced if it breaks. Because they are handmade, there may be some air bubbles, burrs, unevenness, bumps, or dust. Also, they are not as strong as mass-produced items. Thank you for your understanding. We offer discounts for multiple purchases! 50 yen off for each item after the first! Size: 2.5 x 2.5 cm Rubber band size: 3 mm, 5 cm in diameter Please see my profile before purchasing! Thank you!