These wheels are designed to be used as replacement wheels for shopping carts. The listing is for 4 wheels along with the matching axles and nuts. This wheel features a polyurethane tread which protects floors while providing a smooth and quiet roll. It also comes with thread guards to minimize the amount of debris that can get stuck in the wheel. It measures 5” in diameter with a 1-1/4” wide tread width. The axles size is 5/16” and the hub length (where the axle goes through) measure 1-9/16”. The capacity is 250 pounds per wheel. If you have questions, please contact Mapp Caster, we are happy to help.