Zoom Alloy Suspension Seatposts with M6 Hexagon Wrench (27.2MM,30.9MM,31.6MM) Material: Alloy Diameter:27.2/30.9/31.6MM, Length: 350MM, Black. Included a M6 Hexagon wrench for Gift. Seat angle adjustable head-Offset, 1 bolt clamp system. High Quality (ISO 9001,14001)