Color Black Diameter: 11cm Dimensions: 17.5x 11 x 9 cm Package includes: Wheel * 2 Bracket * 2 Screw nut * 2 Fixed buckle * 2 Designed for beginner cycling street exercises to help learners develop a sense of balance on the bike, improve your child's safety and confidence High quality ABS wheels and bracket arms made of high quality steel. Our support arms for training wheels are 3.0 mm thick. For beginners this means more security and stability The support wheels are suitable for most 12-20 inch single speed bikes with a horizontal tie rod end pointing backwards The support wheels are made of high quality rubber and provide the necessary security and stability. Any type of bike looks amazing, stylish and beautiful on really big wheels These wheels are individually adjustable and easy to install. If you have any questions about this item, please feel free to contact us.