A. City road tires perform well on city roads and have relatively low tire noise, so they tend to be quieter. B. These inner tubes are suitable for Zero 10X/Speedual. When installed on Zero/Grace 10, the installation effect on the rear wheel is good. However, when the tire and fender are installed on the front wheel, there may be slight friction between the tire and the fender. C. It should be noted that due to the narrow fender or narrow swing arm, although the pedal hub size seems suitable for the tire, for example, it appears to be suitable for Dualtron 1/2, there might not be enough space for this wider tire. For Track 1/2/3/4 and Inokin fast 1/2/3, they may not be compatible. D. The installation and debugging of the tire require a certain level of hands - on ability. E. The shock - absorbing ability of pneumatic tires is generally better than that of solid tires. But if the inner tube is not inflated regularly, it may be squeezed by the outer tube. F. Color: Black G. Material: Rubber H. Package contents: 2 inner tubes I. Only the above - mentioned package contents are included, and no other products are likely to be included. J. Note: The color of the items in the picture may vary slightly from the actual product due to the shooting light and different displays. The allowable measurement error is +/- 1 - 3 cm.