Environmental protection and health. It is made of high quality environmental protection and high strength PP plastic. UV resistant. Under the action of high temperature, ultraviolet light and light, the activity of polymer molecules inside plastics is enhanced, and the chance of contacting with oxygen molecules is increased, and it is easy to be oxidized. UV has a high energy, can destroy the chemical bond in the plastic, so that the plastic decomposition, we use special formula to slow down the chemical reaction, avoid the product fading. Toughness and strength. Our product is not simply hard on the firmness, we fully consider that hard things will cause compound damage, so we ensure the strength of the product and give full flexibility to avoid breakage and injury. Specification: Diameter11 cm MaterialPlastic andSteel FeatureStable Metal Supports Easy Installment Individually Adjustable Suitable For All Bikes From 12 -20" Inch. Package Include: A pair Bicycle Stabiliser Note Ensure your child is safe when learning to ride