Note: Please measure the actual required diameter before purchasing. Saddle clips are not included, please purchase saddle clips separately if required. Material: The seatpost is made of 6061 aluminum alloy, which is strong and durable. Size-seat tube: 25.4*350 , 25.4*450 , 27.2*350 , 27.2*450 , 28.6*350 , 28.6*450 , 30.4*350 , 30.4*450 , 30.8*350 , 30.8*450 , 31.6*350 , 31.6 *450. Unit (mm) Use and Fit: The seatpost is used on most vintage bicycles, as well as bicycle saddles with clips. Safety Line Marking: There are safety line markings on the seatpost. Please insert at least above the minimum safety line. Features: High-strength aluminum alloy material, CNC integrated molding, surface sandblasting, fine texture and fine workmanship.