gofondo on Instagram: "H&H Titanium Seatpost Matt Grey for #brompton 520mm"
How to assemble H&H DC 3K carbon seatpost for Brompton folding bike - YouTube
H&H Carbon SG Model Seatpost 31.8*520/600mm for Brompton - AliExpress
Amazon.com : Titanium Gooseneck Seat Post for Brompton Bicycle Saddle 31.8mm Folding Bike New Type Rod 550/580mm Gr9 Ti Accessories (550, Gold Color) : Sports & Outdoors