1. Use for 1-1/8" (28.6mm) Stem. 2. These are Brand New Carbon Fiber Headset spacers in 100% carbon fiber. 3. It is 5-10-15-20mm high. It is perfect to get a good fit on your bike. 4. If you need to raise your handle bar, use these spacers. Material: Full Carbon Fiber Diameter: 28.6mm ( 1 1/8") Net Weight: 27g (4PCS)