Brompton Telescopic seat post (pillar) with quick release lever. Lower section is steel, upper section is aluminum.
At full extension telescopic post is 4.5" longer than extended seatpost and 6.75" longer than standard seatpost.
At minimum extension, telescopic post is 0.75" longer than standard seatpost and 1.75" shorter than extended seatpost
Weight 1lb 8.6 oz, (697 g)