Brompton G Line Rear Frame Locking Block
 
The pack consists of:
G Line rear frame locking block
Two springs 
Fixing bolt (CHSS)
 
Tools required for removal:
3mm Allen key / hex wrench
Tools required for installation:
3mm Allen key / hex wrench
To instal put the bike in a stand, remove using a 3mm Allen key, by undoing the bolt.
When replacing insert the two springs into the locking block, line up the cable and screw the bolt through the locking block into the frame, tighten with the 3mm Allen key