Jasper turned his head and barked off to the side so the spray didn't bother him.

The thing about he shock collar is....it doesn't hurt him, becuase he doesn't bark when it's on. It took him exactly two barks to catch on, and now he just knows that when it's on he is quiet.

I can't find it offhand, but I read a study about dogs who wear bark collars, and it turns out that over time the level of cortisol (the stress hormone) present in their blood decreases. Dogs who bark wind themselves up by barking and tend to have constant high levels of cortisol. Dogs who don't wind themselves up by barking are calmer and less stressed over time.

I've certainly noticed a positive change in Jasper's behavior since we started using the shock collar. He used to pant and bark and drool and bark and scratch the front of his kennel and chew up his beds and bark and bark. Now he still pants a little, but he doesn't scratch at the kennel, drool giant puddles onto his bed, or bark. He also hasn't eaten a bed since we started.

We also tried a vibrating collar, which gave Jasper a full on panic attack.

They're certainly not the right solution for every dog, but they are an excellent solution for some.