Sprint Systems Brightening Converter

Has anyone used Sprint Systems End Run Print Brightening Converter?

I posted this question on another forum and have gotten no responses, leading me to think that perhaps there aren't many who have tried it?

Just curious about your results, if any.

I've used it, and it does brighten prints. It wasn't so nice on warm tone papers, but on something like Ilford Multigrade IV it suited well. That paper was pretty bright to begin with; like Hollywood teeth.

I do recall reading that over time this brightener yellowed. That sort of put me off. I'll have to inspect my prints after a few years and see.