Greetings! Just wanted to share my experience with the Citronella bark spray collar. Myah is 2.5 yrs old and we just started using it. Myah is very good in her training, behavior, etc...except for one flaw. She LOVES to hear her own voice when something excites her. I've worked with her in distraction, running through a series of commands, etc -- all work pretty well. But we are in transition between houses (with land) and are in an apartment for just a few months. She cannot bark here.
Enter the citronella collar. Wow. I love it. I've read many reviews that run the gamut from great to horrible, from good device to poorly working device (and perhaps lemons).
Our experience has been good. I got the collar, put the battery in, filled it up (you can't overfill it, and I've found that it works best when full, so it's a morning routine now) and put it on her. It took a while to find the adjustment and the collar seems to slip a bit in size, so I had to bend the strap back through itself to keep it snug.
Myah: one bark and she got sprayed. WTH? Was her response, as she trotted in a circle.
About three times getting only ONE abbreviated "woof" out and she is now a quiet dog. Wow.
I take it off of her at night (because of comfort and because I want her to bark if she hears something at night). I've also tried alternating on/off so she knows when she's wearing it and when she's not. I want her to bark when she should. She seems to understand this (wearing it vs. not wearing it), of which I am pleased.
It has also helped with her socially, as we reintroduce into suburbia and encounter other dogs. She used to let out a bark (woof woof woof!) to approaching dogs to communicate. Now she just keeps on keeping on without the barks.
I'm going to keep working with her to encourage her barks - totally irony here, since I wanted her to sssshhhhhh. But it's been SO effective with her, I want to continue to work with her on this.
I bought tons of extra batteries and citronella refills, but I think we won't need them. I think Myah got the message on her barking and I give the command "no bark" when it sprays. She's smart and trains easily, but this was "the one thing" that was lacking in her almost perfect behavior.
Your mileage may vary. This was just our experience.
Hope it's helpful and I would say the collar is definitely worth a try if you are having a challenge with the bark situation.