This is a Weeride Copilot bicycle attachment. It can be used with any bicycle by clamping it to the tube below the seat. Allows you to ride your bike with a child that is learning to ride a bike without training wheels. Teaches them balance, pedaling and the ability to go on long bike rides with you that will otherwise be impossible because they would not have the endurance to keep up on their own bikes. Tire is 20”, and in like new condition. Frame is in excellent working condition, no rust anywhere. A few cosmetic scuffs here and there, but nothing major. All parts and hardware are included.