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.Mass/Size:11.6g / one size fits allColor:Black,Compatibility:All braze on frames and derailleurs.Adjustability:6mm chainline adjustment provided on the slot for precise setupMaterial:3k CARBON, stainless steel boltNo matter how well you set up the front derailleur with round or oval rings, there is always a possibility that chain may find its way to drop on the frame when you shift quickly from outer ring to inner one. Especially on rough or gravel roads. Mounting chain catcher in front of front derailleur will prevent such occurrence from happening because chain will be guided precisely onto the small ring and will not be able to go any further towards the frame.Our chain catcher has a conical tapered head, providing an excellent fit to braze on mounts that are integrated with frame. However with older frames you may use a clamp braze-on adapter. In such case please ensure that your adapter has a front face also conical (not flat).