Sage, modeling his Kool Collar. They come in a number of different colors.
In a previous post I mentioned the Kool Collar and how well it worked for Denali recently at a dog show when it got to be 90 degrees. It is a great product and really works to cool off a hot dog quickly. (No, I don't get any incentives, nor am I in any way associated with the sale of this item.)
Kool Collars Store has sizes Small, Medium, Large at the cheapest price $15.95 (same as PetCo). I also recommend getting a set of the three gel refills. That way you can keep recycling them through your freezer or ice chest so you always have a frozen one to put in the collar.
This is the only source I've found that also has the Extra Small size for dogs smaller than Denali and Sage. I was pleased to find this because I wasn't able to find a Kool Collar to fit my smaller Pembroke Welsh Corgi, who needs the XS size.
In the Company of Dogs
I'm SO Cool!