Can anyone tell me what this is or how and if it works?

You put that either in front of a intake or exhaust to cool air like a radiator....there are videos on u tube

 

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Per the product details.
It says its a inline duct water cooled heat exchanger. People use it when they don't have ac. It cools air for the lights.

 

you can make your own.... but your going to chew thew lots of ice

you simply run a closed loop 3/4 inch flex line threw your controller and into another tub... fill the tub with ice.. and a inline pump moving the water will help chill the controller...

 

that is going to give you major humidity problems.

 

You have first hand experience? The ones I've seen, humidity is never a concern

 

That's why buckets have lids.

I'm going to be using a similar approach, but with a mini fridge. It's going to be... odd, and possibly dumb. I plan on having 2 reservoirs and having a small one in the mini fridge. With a RDWC it'll pull the cold water from the fridge. I can only hope it works. Unfortunately, the fridge isn't large enough to hold a 3 gallon bucket...

 

what does the bucket having a lid has to do with humidity? your humidity is going to come from evaporated water from that ice machine evaporator. ??? please explain what you mean by the bucket having a lid and humidity. Lol. I don't know if you have a tent or a room, but that mini fridge will be givin off a lot of heat also, that is of course unless the bucket lid solves that problem too, lol.