Bike Training Wheels for 12, 14, 16, 18, and 20 inch variable speed and single speed kids' bikes. Extension bolts are included to solve the problem of installing training wheels on bicycles with short rear axles. The training wheels are easy to install and remove, allowing parents to adjust the height as their child grows. Equipped with rubber tires, these training wheels provide a smooth and comfortable ride. Constructed with a sturdy frame, they can withstand the weight and impact of outdoor use, offering a stable and secure riding experience. The frame is designed for durability and stability. Made from high-quality rubber materials, these bicycle training wheels are slip-resistant and wear-resistant, ensuring reliable performance. Suitable for both boys and girls, these training wheels make a great gift choice for children. Color: Black. Material: Iron + Rubber. Package Contents: 2 x Screws, 2 x Side Wheels. Note: Only the items listed are included. Light reflection and differences in display screens may cause slight variations in color between the image and the actual product. Measurement error allowance is +/- 1-3 cm.