Chain pusher and wing plate set
A$26.00
This is the Brompton derailleur mechanism which pushes the chain tensioner wheels between the two rear sprockets on a two speed or six speed Brompton - it works in conjunction with the DR style chain tensioner.
Complete with wing plate.
The chain tensioner has not changed from the pre-2017 to the 2017 onwards integrated shifter derailleur - so is compatible with all year Bromptons (as long as it has the hexagonal braise on the rear triangle for connecting the wing plate)
Note: there is a 'crack' in the wing plate to allow expansion of due to the paint on the Brompton frame.