Hub gear indicator chains for Sturmey Archer hubs

The gear indicator change is cable actuated and pulls a clutch in the centre of the hub to change gear

Different hubs have different indicator chains - the length and width can vary

Most of the Sturmey Archer indicator chains have a mark on them to aid with identification - for example the Mark 2 chain used on the Brompton BWR and BSR has "SA II" etched into the side of the indicator chain axle

Later gear indicator chains moved away from using engraved version numbers to colour markings - these can look similar, so need to be seen under good daylight!

Also note that the chain can be very dirty when removed from the wheel - so may need cleaning