Recommendation for cooling vest

[Beccabunny]

I'm looking for suggestions for what kind of cooling vest to purchase for DD12. I need something that will stay cool for at least four hours in the parks in May, when I expect the temps could be in the low 90's. CoolMedics makes one that she could also use for horseback riding, but it is the evaporative type that you soak in water as opposed to the kind that has cooling packs. I've read some reviews that said it can be heavy and also leave your clothes wet. Has anyone had this kind of experience? Would the more expensive vest with cooling packs work better? TIA!