These types of collars spray citronella into a dog's face everyone he or she barks over a certain decimal or tone. Many people think this is a better option that the other collars that shock the dog when he/she barks loudly.
Dogs have extremely sensitive noses. Smelling and hearing are what dog's biggest attributes.
It is estimated that at minimum a dog has over 100 million more smell-sensitive receptors. Some breeds reach into the 300 million range. It is because of this dogs can smell and decipher scents 100,000x lower than people are able.
There are conflicting facts actually to the extent of how much greater a dog's sense of smell is greater than humans but we do know for a fact that it is huge!
What is my point? Obviously, your dog has an extremely sensitive nose.

A citronella spray, which is actually a strong yet non-toxic way to repel mosquitoes, bothers them. There is something about that smell that dog's just loath.
When a dog barks loudly, his or her anti bark spray collar goes off, and shoots out the citronella odor I would say it is the equivalent to someone touches your eyeball.
Your eyes are very sensitive and the slightest touch is unpleasant. It will not kill you but someone touching your eyeball is definitely not a sensation you would look forward to. The same is true when they get sprayed.
This citronella spray will definitely not kill them, not even hurt your dog, but it will mess with their most sensitive feature enough (their nose) to make the STOP doing what they are currently doing.
Some dog owners have claimed that these anti bark spray collars work better than the usually anti bark shock collars.
Whether they are as effective or not, I cannot say for absolute sure. I do know they work.
When you use these collars, please, make sure it is snug around your dog's neck. If it is not then its sensor will not be able to detect the bark. If he or she has a thick coat of hair you will have to shave it off. Hair is the biggest barrier to these citronella anti bark collars working.
Make sure it has a full cartridge at all time and watch what happens. You will notice, and I might add quickly, that this device solves your problem.
All it will take is several loud barks and the spray will be released in front of your dog. It happens quick and the spray is not big, just a really small and quick burst.
Your dog will be confused at first but quickly get the message. The days of incessant barking are over and you, and your neighbors, can have some piece of quiet