High quality material and size: 18"20"size steel spokes high carbon steel frame high toughness high carbon steel frame heat treatment technology tough masculine tough. Safety: front and rear mechanical disc brakes stop and stop strong braking easy and safe brakes aluminum alloy sprocket wheel protection chain does not fall off stepping on force. Manufacturered by Axdwfd. Versatile: Adjustable handle height for adjustable seat height 7-speed adjustment is more convenient. Features: Heavy-duty detachable adjustable stabilizer simple high or low stabilizer wheel position for different learning stages. This sporty bike for boys and girls comes with training wheels and a quick release seatpost which makes it easy to adjust the height of the seat .