Zipp have taken their pro proven service course sl 350mm seatpost and made it better the redesigned post is now lighter weighing in at 235g for the 20mm setback model and 220g for the 0mm setback model because they are lighter this doesnt mean they are any less stiff zipp boast that they are just as stiff and also feature more precise fitting and easier tool access for the downward facing bolt needed when setting up