Bike seatposts explained: diameters, materials, lengths and more
KINEKT Active Suspension Seatpost and Stem – KINEKT Store
Bike Seatpost φ27.2 30.9 31.6mm Extender Length 400mm—Upanbike
Amazon.com : FIFTY-FIFTY Mountain Bike Saddle, Comfortable Memory Foam Bike Seat, Mountain Bike Seatpost, 27.2mm Aluminum Alloy Bicycle Seat Post, 350mm Length for MTB, Road Bike : Sports & Outdoors