Fito Aluminum Alloy 25.4 x 350 mm Bicycle Seat Post Seatpost. Mount Diameter: 22.2mm (7/8") - Black BRAND NEW HIGH QUALITY MADE BY FITO. MATERIAL: LIGHT WEIGHT & ANTI-RUST ALUMINUM ALLOY. SEAT POST DIAMETER: 25.4MM(O.D.). SEAT POST CLAMP MOUNT DIAMETER: 22.2MM (O.D.). LENGTH: 350MM. FOR BEACH CRUISER BIKES, MOUNTAIN BIKES, TANDEM BIKES, COMFORT BIKES, AND BMX BIKES.