Ultra-Pure Light bearing oil is used to oil the rotating bearings on the top and bottom of rotary valves.
Modern French horn rotary valves require three different grades of oil. From thickest to thinnest they are: bearing oil, linkage oil and rotor oil. Apply the first two each week, if you play regularly. When a valve become sluggish, drip a tiny quantity of rotor oil directly into the rotor casing, having first removed the valve slide to allow access.
For reference, a maintenance schedule recommended by the Rosehill workshop is included alongside the product image(s).
Sorry, we do not have any details for this product