Pre-2017 Bromptons have the gear cable the reverse way round with the head inside the derailleur and the cable clamp inside the two speed shift lever. That kit is for a cable clamp to go the derailleur end which means you can use a non-Brompton shifter on those bikes.
You don't need it on post-2017 bikes, as the setup is already conventional.
Pre-2017 Bromptons have the gear cable the reverse way round with the head inside the derailleur and the cable clamp inside the two speed shift lever. That kit is for a cable clamp to go the derailleur end which means you can use a non-Brompton shifter on those bikes.
You don't need it on post-2017 bikes, as the setup is already conventional.