Chốt chặn cốt yên Brompton (Brompton Seatpoststopper)

This part slots into the lower member of the rear triangle (as seen in the picture) and is held in place by a cable tie. The cable tie is non-load bearing. Should fit all 16“ Bromptons, allthough ive only tried it on my brompton from the early to mid 90’s. Let me know if it fits your bike.