This oil solved the problems I was having with my new Cerveny rotary flugelhorn. I started oiling it with piston valve oil as had been recommended to me by several people. This produced big problems with the third valve as it would be gone very quickly so the valve would start to grind (not in a bad way, but like it was not oiled due to the close tolerance).
After using this oil instead, the third valve runs smoothly, although it still needs more regular oiling than the other valves (applied by putting drops of oil down the middle valve and running it down the instrument). The regular oiling is probably due to the oil being washed down the instrument, rather than evaporation, as it is both thick and synthetic so is likely to evaporate very slowly.
I also used this oil for very loose valves of a Besson cornet I am selling, which helped to seal them.
There is also 5ml more than the Hetman 10 and 11 rotary oils. Bargain!