absoluteBLACK Chain Catcher is designed to eliminate the possibility of chain falling in towards the frame when shifting to the inner chainring on uneven road. Chain Catcher is a simple add-on component which improves the overall function of your drive train and protects your valuable frame from dropped chains. Especially recommended for Carbon frames. Adjustability: 6mm chainline adjustment provided on the slot for precise setup Mass/Size: 11.6g / one size fits all