Universal diameter and available size This wheel is designed to fit multiple kid bicycles with a bracket that attaches via five mounting holes. It supports bicycles in sizes 12, 14, 16, 18, and 20 inches. The wheel has a round, blue appearance that is appealing to children. Note: Not compatible with variablespeed bicycles. Double and larger washer The wheel uses double carbon steel components optimized for quiet operation and long life. The washer is enlarged to provide full coverage and a secure fit. This helps prevent looseness after riding sessions, reducing the risk of sudden detachment and keeping your child safer while riding. Thickened wheel with quality PU material The wheel is made from quality PU material for quiet operation and durability. The wheel thickness is 2.5 cm (0.5 cm thicker than standard), which helps absorb bumps, reduce effort, and provide a more comfortable ride. Use scenarios Kids' daily rides: worn wheels on a 12–20 inch bike to improve safety, quietness, and comfort during neighborhood rides and park trips. Growing families: A single wheel can serve multiple bikes as children grow, simplifying upgrades and maintenance across different bicycles. Light commuting and casual rides: Enjoy smoother rides on smooth surfaces with better shock absorption and reduced bumpiness for short trips to school or friends' houses. Key benefits at a glance Broad compatibility: bracket with five holes fits 12, 14, 16, 18, and 20 inch bikes. Safe and durable: enlarged washer and double carbon steel construction for reliability and reduced loosening. Quiet and comfortable: PU material delivers smooth, lownoise operation and improved shock absorption. Enhanced ride feel: thicker 2.5 cm wheel reduces bumps and makes riding easier and more comfortable. Childfriendly visuals: round, blue appearance that appeals to kids.