KINGSO Alloy Seat Post Clamp for Bike Bicycle Mountain Bike Quick Release Black 31.8 mm Material:Aluminum alloy Size:34.9mm/1.37" Package Content:1pcs seat post clamp Applies to 27.2,28.6,30.4,30.8,31.6 seatpost diameter For holding the seat lever to the position,there is no need for any tools allow for your convenience on the road seat height adjustment