RE: What do you use for a watering system
I have seen those too. They work well.
We use a garden sprayer (marked K-9 ONLY) to wet them down on warm days. We carry Gatorade bottles with the twist tops in our vests. In my SUV, I carry a 3 gallon container that has a push button spout on it. In the big truck we have a 5 gallon plastic gas can (marked K-9 only). We bought the sprayer & can new and have used them for these purposes only.
We also fill and freeze empty milk/juice containers so they can thaw out for the dogs. They pull double duty, ice for the trip out, water from home for the dogs...