This was an excellent modification to the Brompton P-Line that I got from the San Francisco shop a year ago. Any weight shaving is a plus to the already manageable P-Line. Slightly longer than the standard seatpost, it allows me to push the folded bike by the seat and still engage the lock so I can carry it as needed on stairs without adjusting. I can tell it does flex to help over rougher roads. A titanium seatpost is a mod must.