I didn't find that it helped Jackson all that much so I returned it. But then again, he never had MAJOR fear of storms. He's very afraid of fireworks but we rarely encounter those and we were lucky enough to bypass them all this year.
Last night, we had some brutal thunderstorms, and the night before, too. And all day on/off today. He doesn't like them but he's been fairly calm throughout. Occasionally he goes under the bed during the big booms. But I didn't feel the amount of fear he had warranted the $40 shirt so I returned it, lol.
But many others have had AMAZING success.