Two size available: These bands are small size wrist bands( 4.7~6.2inch) Usually not fit 8 years or older. We also have the larger size bands(6~8.5inch, ASIN: B078Q4G26Y) If the band too small for the wrist, you could contact us freely, we will send you the larger size for free. Is the skin red after wearing the replacement band? If the band is worn tightly, skin redness may occur after exercise, which may be caused by skin sweating, airtightness, or prolonged friction and restraint. Therefore, it is not recommended to wear the band too tightly, make it move back and forth on the wrist. But if the redness area cannot be recovered for a long time, or itchy symptoms, please consult your doctor in time. Return issues caused by product quality: If there is a problem with the quality of the product, please provide us with a picture, we will resend it for you or give you a full refund, and you do not need to return it. Customer service: If for any reason you are unhappy with any product by RuenTech, please feel free to contact us. We take full ownership and responsibility for the quality of our products and will do our best to solve your problem quickly and efficiently!