Used on the shaft of a steam turbine model engine and performed above expectations reaching upwards of 100 000rpm without any stress. The company acted in a professional and curteous manner and even suggested another company when I asked a technical question they couldn't answer concerning a particular type of bearing. Super company to deal with. I would use them again. Very fast delivery from the USA perfect. The bearings were not a gift and I haven't received any payment or compensation for writing this review.