Carbon Fiber Bike Headset 1-1/8" Stem 5-10-15-20mm 4pcs Set Use for 1-1/8" (28.6mm) Stem These are Brand New Carbon Fiber Headset spacers in 100% carbon fiber. These are for oversize forks and stems at 1 1/8". It is 5-10-15mm high. It is perfect to get a good fit on your bike. Material: Full Carbon Fiber Diameter: 28.6mm( 1 1/8")