Specification MaterialAluminum alloy BearingCeramic bearingColorRedFit for4 5 6 mm roller screw axisSize12T13T14T15T16T17TFeatures Made from high quality aluminum alloy 7075 material which is not only durable but also solid and practical It is very easy and convenient to install it cost you just a little time on its installation which can save you energy and time Built to greatly strict quality control standards resulting in its stable and excellent performance 2 color to choose its nice appearance will make you bicycle more attractive Exquisite workmanship and high quality product will service a more wonderful and longer life for you than any other similar products 12T 13T 14T 15T 16T 17T to choose Package included 1 x Derailleur