Glad you found it!
I've quit using regular horse fly spray. They never last more than a few hours, less if the horse is sweating profusely. I use Deep Woods Off. It's cheaper than fly spray and it works great and we both can use the same thing. It keeps ticks off too.
I was right about where it was though ;~D
I'm kind of sold on Pryhana. Have you ever tried it. It's mid range price, and I have had great luck with it. I told Mack that or nothing. I've tried the more expensive one's and was not impressed.
Becky
Last year we used cattle tags made by Bayer. They did an excellent job, and last for about 3 months.