This thing saved us on a hot hike during a summer heat wave. Super easy to dip it in a lake or stream, pop it on her neck, and voila. After a few seconds my dog seemed to start cooling down quickly and she was in a much better mood. We also have a swamp cooler that goes on her Webmaster harness - by comparison, the neck gaiter stays cleaner and is easier to soak and re-soak. It's also easy to stuff it in a pocket to have in hand in case it gets hot.
Just remember to keep any swamp cooling gear wet, otherwise it just becomes an insulating layer.