Size: Bearing inner diameter: 21 mm / * Inner diameter: 6 mm / * Wheel diameter: 50 mm / * Thickness: 18 mm / * Length of Axle: 36mm. Installation: Simple luggage rollers, without professional instructions, can be installed by yourself, very convenient. Also make sure to waterproofing of the wheel at the time of installation, so that the luggage rollers can roll better. Benefits: Quality replacement wheels. superior. Durable, quiet, load-bearing, double bearing, flexible rotation. Load: a single suitcase can hold up to 100 kg. 51 kg, without deviation of the phenomenon for safe and reliable use. Cleaning: The suitcase replacement wheels are easy to clean. clean and the wheels can be removed for cleaning. Buyers should measure the data of the following suitcase wheels to know what size they are capable of rolling: < br />1, Measuring the original outer diameter wheels (wheel size). 2, The inside of the groove width of the measuring wheel (width of total installed width). 3, at through