Included: 2 x wheels, 2 x brackets, 2 x screws, 2 x washers, 2 x screw caps, 2 fixing codes, 1 x wrench We provide a complete installation tool, so it is easy to quickly install the training wheel on your bicycle.Material: These bicycle training wheels are made of high quality plastic and rubbe. The wheel diameter is 11cm and the thickness is 2.9cm Suitable for most 12 inch to 20 inch single-speed bikes.Thickened design: thicker design makes the wheels more wear-resistant, stable The high-quality materials used are non-slip and noiseless. It will be safer and more stable for beginners.Safe and Stable These rear wheels provide the necessary safety and stability for the children's first bicycle attempt, and give them a good start with confidence and love for the sport.100 percent MONEY-BACK GUARANTEE: If you have any concern about this product, you can contact us by email and we will answer you within 24 hours. If the purchase has some quality defect, we offer a 60 days money back guarantee, you can also ask for a NEW DELIVERY for free.