Compatible with 12, 14, 16, 18 and 20 inch wheel bikes, these training wheels are designed for both single speed and variable speed kids bikes. Extension bolts help solve the common issue of fitting on bicycles with short rear axles. Key benefits Safe, stable riding for beginners: sturdy frame and rubber tires provide a secure, smooth ride as children learn to balance. Easy growth adjustment: height can be adjusted as your child grows, extending the usable life of the wheels. Durable and reliable: built to withstand outdoor use with a robust frame and wearresistant rubber tires. Product details Size compatibility: suitable for 12, 14, 16, 18, and 20 inch bikes; supports both single speed and variable speed configurations. Extension bolts: included or used to fit bikes with short rear axles, enabling a secure installation. Materials and construction: quality rubber tires for grip and a slipresistant, wearresistant riding experience; a sturdy frame designed for outdoor use. Installation and maintenance Simple installation and removal: quickly attach or remove the training wheels as needed. Adjustable height: tailor the wheel height to your child's skill level and height as they grow. Ride comfort: rubber tires provide a smooth, comfortable ride for your little rider. Use scenarios Learning at home: ideal for firsttime riders practicing balance on flat driveways or paved paths. Park and neighborhood rides: stable support on gentle inclines and uneven sidewalks, helping kids gain confidence outside the driveway. Growing with your child: as your child grows taller and more capable, easily adjust the training wheel height to continue providing reliable support during progression to independent cycling.