Specialized Alpinist Seatpost 27.2mm x 300mm - No Boundaries Sport
GEWAGE Suspension Seatpost for Bicycles - 27.2/30.9/31.6 X 400mm Shock Absorbing Bike Seatposts - Lightweight Aluminum Alloy Seat Post for MTB Road Bike BMX eBike - Walmart.com
Amazon.com : 27.2 Seatpost 400mm LITEONE MTB Seat Post with 28.6mm 30.9mm 31.6mm Seatpost Shim Suitable for Mountain Bike Road Bicycle MTN BMX ( Include 3 Tube Adapters 15mm Setback ) : Sports & Outdoors