MagiDeal Aluminium Alloy 31.8mm/34.9mm Quick Release Mountain Road MTB Bike Bicycle Seatpost Seat Post Clamp Tube Clip - Black, 31.8 mm Aluminum alloy material, high quality, long service life Convenient design, simple installation Material: Aluminum alloy Caliber: 31.8mm(1.25inch) / 34.9mm(1.37inch) Color: Black, Red, Blue, Silver, Gold