Chain hook for derailleur powdercoated black incl M5x25 bolt for Brompton
This hook can be attached to a rear derailleur, not all derailleurs are tested, just a few. It's specifically designed for a Shimano Zee derailleur. The length can be slightly adjusted by means of the slots. It's purpose is to take up the excess length when the Brompton with derailleur gears is folded. On Shimano Shadow derailleurs it's recommended to be used in conjunction with a Diabolo and bungees cut from Brompton inner tube to create B tension. Classic non Shadow derailleurs already have B tension with a build in spring.