This product is suitable for some Huffy brand bicycles and other brands with 3/8-26TPI rear axle. Please ask the corresponding brand service provider by email or phone again before purchasing. Make sure the product is correct, so as not to affect your child's mood. This product is suitable for some Huffy brand bicycles with 3/8-26TPI rear axle, please ask Huffy service email for the corresponding model rear axle size before purchase. Product dimensions: 3/8" × 26TPI × 4.5cm Are you frustrated when your child receives the expected training wheels that can't be installed? That's when you need it. Includes 2 Extension bolts for bike heavey duty training wheels. These extension bolts are appropriate fit to the bike If you don't know the size of your bike's rear axle, it is recommended that you go to a repair store and ask about it first.