Carbon Fiber Bicycle Headset Spacers 1-1/8" Set Stem Set 5-10-15-20mm 4 Pcs Brand new, never been used or installed. Material: Full Carbon It is 5-10-15-20mm high. It is perfect to get a good fit on your bike. Fixed Bolt Seat Clamp for Better Seatpost Security, Theft Prevention If you need to raise your handle bar, use these spacers.