Syloxi is Rolex's proprietary silicon hairspring, developed to enhance the performance and reliability of its watch movements.
Syloxi is Rolex's proprietary silicon-based hairspring material, developed as an alternative to traditional Nivarox alloy hairsprings. Silicon hairsprings are inherently non-magnetic, significantly reducing the watch's susceptibility to magnetic fields without needing a soft-iron cage. They're also highly resistant to temperature variations and require no lubrication at the escapement level.
Syloxi silicon hairsprings are non-magnetic (Nivarox alloys have some residual ferromagnetism), more thermally stable, and don't require lubrication at the pallet fork and escape wheel interface when paired with silicon escape wheels. However, Nivarox hairsprings have centuries of refinement and remain the industry standard in most movements, while silicon hairsprings require specialized microfabrication techniques unavailable to most manufacturers.
Rolex introduced Syloxi hairsprings in their Calibre 2236 movement, used in the Ladies' Oyster Perpetual line including the Datejust 31 and Lady-Datejust. The Syloxi hairspring is combined with the Chronergy escapement (silicon escape wheel and pallet fork) to create a movement that's highly resistant to magnetic fields and temperature variations. Rolex's broader adoption of silicon components continues to expand across their movement lineup.