Bark Control?

I have 4 chihuahuas and my parents/little brother have a yorkie/chihuahua mix. They tend to bark for no reason and I was hoping to stop it. Barking some is fine, they are dogs and are going to bark. Barking outside is no big deal...bark all day long outside if they want. It's the days that they seem to bark non stop while inside for no reason that drives me nuts.



Since there is 5 of them, I'd like one device to help control them all from barking so much inside, rather than getting each one a collar. Also, don't want anything that shocks, zaps, or whatever.

I've seen these items online, but wasn't sure how well they worked.



Seems kind of cheap, which makes me weary.

http://ift.tt/1BnddD1



Hand-held (might be easier to start with, but have to keep it with you at all times)

http://ift.tt/1BnddD1



Another indoor unit

http://ift.tt/1DJERhi



If anyone has any experience with it, please let me know what you used to control it. Or used one of the things listed above or another product?