This Schwinn replacement tube is specifically designed for 28-inch bicycle tires. It is made of high-quality rubber material and features a Schrader valve type. The tube size ranges from 35mm-42mm and is suitable for use with a variety of bicycles. This pack includes two tubes, making it a great value for cyclists who need to replace their existing tubes. Additionally, this product is manufactured in Taiwan and is compatible with a range of biking conditions.