Vktech&reg; Hot GUB GS Ultra Light Weight Aluminium Bike Bicycle Seat Post 30.9MM Premium quality seat post at a fantastic price, these are as good as they look. Incredibly light and strong, without breaking the bank Type Item: GUB GS ultra-light aluminium alloy seat post Seatpost Diameter: 30.9mm Length: 385mm Material: 6061 Alloy T6 heat treating