Vision Metron Seatpost - 27.2 x 350mm 0mm Offset CarbonVision Metron Seatpost 27. 2 x 350mm 0mm Offset Carbon. A good seatpost is essential for consistent power delivery against the clock. The Metron post delivers with carbon fiber monocoque construction that combines the shaft and head into a single strong yet lightweight piece. The post is topped off with a forged alloy Minimal Top Clamp for secure saddle location. Simple two bolt adjustment allows fine control of your saddle angle so its easy to get