The FSA Orbit Xtreme Pro threadless headset is constructed of forged and CNC machined 7075/T6 aluminum cups. - Stainless steel Angular Contact Bearings - Stainless steel crown race - 1.5'' patented alignment tip for increased durability and performance - Deep Cup model has 22mm insertion of upper and lower cups

- Carbon fiber top cover - Upper: Campagnolo angular contact bearings (black seal) - 1-1/8-inch, 45 degrees/ 45 degrees ACB upper - 1.5-inch, 36 degrees/ 45 degrees ACB lower - For tapered 46mm/56mm OD headtube - For 1-1/8-inch to 1.5-inch tapered fork

- 1-1/8" / 1-1/4", 45°/ 45° ACB - Compatible with carbon or alloy head tubes - For tapered 47mm / 52mm OD head tube - For 1-1/8" to 1-1/4" tapered fork - Alloy top cover - Upper : 1-1/8" angular contact bearing black seal) - Lower : 1-1/4" angular contact bearing (black seal) - Stack height 15.6+1=16.6mm - 74 grams

FSA Standard Headset Bearings

FSA bearings that set directly into the frame without the use of pressed in cups. - 36/45 degrees is Cane Creek-compatible - 45/45 degrees is Campagnolo-compatible

Replacement headset bearings from FSA. - Compatible with most Trek MTB integrated headset systems - Sealed bearing for long life - Compatible with Knock Block Headsets

- Forged steel cups with caged 5/32" ball bearings - TH-857 features a alloy top cover - TH Series: External Cup, traditional - S.H.I.S.: EC34/28.6|EC34/30 - Stack: 14.9mm/11mm - Color: Black - Weight: 126g

FSA bearings that set directly into the frame without the use of pressed in cups. - 36/45 degrees is Cane Creek-compatible - 45/45 degrees is Campagnolo-compatible