The Brompton Standard Length Steel Seat Post in Silver is designed specifically for Brompton folding bikes. Made of durable steel with a diameter of 30.2mm and a length of 540mm, this seat post is a genuine Brompton brand product from the United Kingdom. It is a single unit weighing 400g, suitable for Brompton A line or C line bikes and compatible with the brand's unique specifications. Top of seat post tube is reduced to 20mm for saddle connection. Length is 42mm. Bottom of seat post tube is flared to accommodate seat bung 32mm. This is a seat post specifically for a Brompton folding bicycle. I cannot guarantee it will fit any other bicycle.
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