Keep Your Child Safe and Confident - These 3mm thicker utility bike training wheels have added reinforcement clips to create a sturdy triangular design that helps learners develop a usable sense of balance on the bike and saves kids from riding the bike Worry about wrestling High Quality Flash Wheels - Non-slip, wear-resistant and stable, the training wheel stand arms are 3.0mm thick, these will be more secure and stable for beginners. Black wheels are perfect for any color bike. Universal & Adjustable - Support Wheels Fit 12/ 14/ 16/ 18/ 20 Inch Single Speed Bikes with Horizontal Rearward Track Fork Ends, but Not Fits Semi-horizontal or Vertical Dropouts. Cannot be mounted on bicycles with derailleurs or derailleurs Easy to Install - Includes 2 Vertical Stand Arms, 2 Wheels, 4 Nuts (2 Spare Nuts), 1 Screwdriver, 1 Wrench, 1 Bike Bell. Enjoy your first outdoor bike ride with your kids Installation - 1. Connect the training wheel and support bar together. First install the screws, training wheels, spacers, support rods and nuts in sequence, and then fix them with a wrench.