EIS S9 Carbon Seatpost - 30.9 x 350mm Go to amazon.com Related posts The 10 best 30.9 seatpost carbon FeatureEIS - S9 30.9mm x 350mm Description* A fine balance of weight, stiffness, and comfort * Optimal density carbon fiber with alloy clamp * 350mm length * 5mm offset * 185g (31.6mm)