FIT FOR ROCK BROS Suction Cup Bike Rack Adapters for suction cup bike rack is suitable for ROCK BROS bike sucker rack EASY TO USE The adapter is easy operation It only takes you a few seconds to install it following the installation video COMPATIBILITY Fit for most mountain bikes road bikes trail bike or any bike with a quick release front wheel DURABLE Adapters are made of good materials can be used for a long time SUITABLE BIKE RACK ADAPTER 9121520mm Diameter 100110mm Axle Length please choose suitable adapter for your bike rack Or please let us know if you have any questions