When young children start to ride a bike, the they need to gain is a sense of balance. Training wheels or stabilizers are an additional wheel or wheels mounted parallel to the rear wheel of a bicycles that assist learners until they have developed a usable sense of balance on the bicycles. Features -Color:Black -Material:Steel and plastic -Size (wheel):10.50X10.50X2.50cm/4.13X4.13X0.98in -Size (rack):17.50X9.00X9.00cm/6.88X3.54X3.54in -Made of good steel and plastic material, which can be firm and durable. -Made with a strengthened reinforcement design that adds unprecedented stability and safety. -When the children learn to ride a bike, balance is the first and the most important thing they need. -The overall bracket and wheels are thicker, stronger and easier to install than regular wheels. -Effectively help your child learn to ride a bike without difficulties, improving your child's safety and confidence. Package list: 1 x Pair of Training Wheels