The weather in Ohio has not gotten to warm yet so I can’t really comment on the effects of the product. I have recommended it to some of my golf league friends who intend on buying some. Check back in July ans I can give you a real evaluation
I used HatSaver on a light blue golf cap. A couple of days later I worked up a sweat walking 18 holes and taking too many swings. I expected to see a few wet spots on my hat when I was done with round, but there was NOTHING! No Drips. No Stains. No Sweat Spots. This product definitely works well!
Works way better then expected I own a landscaping business and I burn through hats from sweat and dirt, this stuff is legit didn't even realize it would keep my hats clean!