Unlike humans, dogs can’t sweat to cool off. The Dog Vest absorbs a dog’s excess body heat, allowing the canine to work or play harder and longer in extreme temperatures.

This cooling dog vest doesn't use ice packs or gel packs, but something the manufacturer refers to as a "phase changing substance".

Instead of freezing at 32°F, it freezes at 50°F, meaning you can "recharge" it much more quickly than with ice packs or gel packs.
Available only in large size, you can buy it online for $75.00.