Size: 50mm x 18mm Package: 4 wheels, installation kit Installation: A simple luggage roller that can be installed by yourself without professional help, which is very convenient. When installing, pay attention to the tightness of the wheels so that the luggage casters can roll better. Advantages: High-quality replacement wheels. Durable, quiet, load-bearing, double bearings, flexible in rotation. Load-bearing: A single suitcase can carry up to 51 kilograms without deviation, making it safe and reliable to use. Cleaning: The replacement suitcase casters are easy to clean and can be removed for cleaning. Buyers should measure the following suitcase wheels to see how much they can roll: 1. Measure the original outer diameter of the wheel (wheel size). 2. Measure the width of the groove inside the wheel (the width is the total installation width). 3. Measure the screw length (without nuts at both ends). 4. Measure the diameter and width of the bearing hole in the thickness of the tube.