That was a "wipe on" headlight treatment. It looked a little crappy afterwards, and it hazed up within a year.

The best I've tried so far is the 3M headlight treatment, but you also need to hit it with a headlight sealer, which is sort of like a "clear coat" for headlights. That should be good for a couple years.

Next up is a Cerakote Ceramic Headlight Restoration kit. It's supposed to protect for the life of the headlights. Fingers crossed! I didn't think to order it until the night before my inspection last year. I had the Rain-X kit laying around, so I went with it. Had I known the results, I would have used WD-40 for last year's inspection, then applied the Cerakote kit when it arrived.