The SEYOUN 20-inch bicycle inner tube is a reliable maintenance accessory designed for standard, city, or folding bikes. Made from natural rubber, it features a reinforced structure that helps the tube withstand high compression and mechanical shocks during your rides. To make installation easier, the packaging includes a green-red graphic marker that provides clear guidance for proper inflation. This ensures you can maintain the correct tire pressure for a smoother and safer journey on your daily commute.