This is the best investement when it comes to reducing weight on your Brompton folding bike.  Replace your heavy metal seatpost with this premium quality titanium seatpost. It's made exactly like your factory Brompton seatpost and utilizes your existing Brompton Pentaclip so that you can have the best possible saddle adjustment. You will save about 182 grams from your factory metal seatpost. Maximum weight allowed is 180 lbs. Installs in minutes.