This high-quality FSA upper headset bearing, with dimensions of 1-1/4" and a 45°x45° angle, is designed to fit several Cervelo frames. It is compatible with the Aspero-5 (2022-present), Caledonia-5 (2021-present), R5 Disc (2023-present), R5CX (2023-present), S3/S-Series Rim (2019), S3/S-Series Disc (2019-2020), and Soloist (2023-present) models, ensuring a precise fit and smooth performance for these Cervelo bikes.