This is a nice a vest that helps you cool down. I've seen some negative reviews about it not working. The key to this thing is that it will only work when you are indeed starting to heat up. If you're just sitting in the car, or outside for a short period or not really getting the body temps up, this thing won't do anything. I only notice this vest working when I'm outside for an extended period and I'm starting to sweat. When I hit that point, and my shirt starts to wick the sweat, I can feel the cooler air breeze through my vest, and there is a legit cooling effect because the air passing by is cooler and it's passing through a sweat wicking shirt that is damp from your shirt. I do wear an external carrier style vest, so air does pass through rather easy. Not sure how much air you're going to have pass through if you wear this with a polyester style uniform. But when it's hot outside and you're doing something like directing traffic, and you're starting to sweat, this thing will help you keep that sweat wicking shirt evaporate the sweat. This is not a vest where there is cool water is being pumped through and keeping you constantly cool. it's passive and will work when you're hot.

I'm taking one star off because the back pieces must have some lose material because it pokes me in the back. They are hard springy like strands that suspend the vest. if they get lose from holding together, they poke you in the back and they're pretty stiff (think cleaning brush strands)

I wore it for a while and did not notice it cooling me too much more than when I didn't wear it. It worked better with my outer carrier.

Works well while driving but if you sit for to long it does not breath as well as I would like. Other then that it works as advertised.

I don't have the sweat outline of the vest after a long day at work, and I get good ventilation. Great product for LEOs if you work in hot areas.

Definitely feel the difference in ventilation. Especially when you hang your arm out the window. Highly recommend, even to try it.