THIS IS A TRAINING WHEEL SET FOR 20 INCH AND 26 INCH WHEEL BIKES AND ADULT BIKES BEST STRONG SET I COULD FIND TO SELL IN OUR BIKE SHOP, EASY TO INSTALL, NICE STRONG STEEL BRACKETS, NICE RUBBER TIRES, I HAVE SOLD THE WHEELS ALONE FOR PEOPLE WHO NEED THEM FOR CARTS AND OTHER THINGS LIKE THAT.