F+ Silver titanium 540mm seat post for Brompton folding bike.
Original Brompton seat post weight 390g.
Made through one-piece titanium. It will not get rusty, the end of pole has special design to prevent separation with the bike frame. Seat post thickness is 1.1mm.
Video for assembly titanium seat post:
H&H DESIGN, carbon, seat post$133.00
H&H DESIGN, frame clamps, seat post$85.00