Black Brompton seatpost - standard length This is the standard length Brompton seatpost - made of steel - but painted BLACK as supplied with the BLACK edition Brompton bicycle and made available to the after-market in 2016 (In the early days of Brompton they used a titanium seatpost, then later there was also an aluminium seatpost available - these have now been discontinued - titanium due to supply issues and aluminium due to long term quality issues - the coating discoloured over time) The Brompton seatpost has a 31.6 mm diameter through most of its length (with a flange at one end to stop it raising too far and a narrower end for the saddle to attach to) Length: 53.5cm / 21 inches The seatpost is installed on the Brompton from underneath (the flange at the bottom stops the seatpost being raised too far) Remember: Never lubricate the seatpost