Anti-Bark or No-Bark Collars use four different methods to combat nuisance barking associated with most dogs. Each type of collar provides an effective solution depending on the pet, surroundings, circumstances and available adjustments provided dependent upon the manufacturer of the product.
The first method that has become known as the "humane" treatment against a barking pet uses a scented spray to stop their barking. This system combines electronic monitoring and "spray technology". This is an excellent deterrent and behavior modifying technique to stop excessive barking.
The basic premise is to redirect their thought process and therefore their behavior to a less aggressive state. The collars use Citronella spray in a refillable canister. Since this smell is not normally encountered by your pet it is unusual enough to distract them and interrupt the bad behavior.
The spray is harmless to the pet and the surrounding areas. It is also formulated to be stain free so it doesn't mess up items it may come in contact with. There have been many studies on Anti-Bark and No Bark collars as to their effectiveness to stopping the barking and training the pet not to bark when unnecessary.
Tests conducted on over 1000 dogs showed more than 70% stopped barking within days of the first use. Over 90% stopped within 2 weeks. Although effective each situation and pet is different. That's why the second type may be necessary for your pet.
The second type of collar uses a 2-step process to stop the dog from barking. It uses either a microphone or vocal cord vibration sensor to detect the barking. Once it does it will deliver a static shock to the pet similar to when to walk across the rug and get a shock when you touch another person or metal object.
The better Anti-Bark systems can be adjusted for different correction modes with each mode having up to 10 different levels of the static shock. The device also has a safety built in so as to not over correct the pet if they bark incessantly and will turn off for 3 minutes then restart the process. This happens if the dog barks 15 times within 50 seconds. Each manufacturer that offers this safety has different time frames built in.
The third type of system is used within the confines of an area, where a barking dog will be staying. These devices http://edition.cnn.com/search/?text=bark collar use what are called Ultrasonic Tones that can only be heard by pets. When a dog barks, the system recognizes the bark and emits the tone.
These sound waves humanely stop them from barking with the high pitched sounds. Depending on the model and adjustment of the bark sensitivity control, these products can work up to 75 feet from where they are placed.
The last method uses a system of remote control. They work either with a Citronella spray or a static electronic shock. They are used so that the owner can "train" the dog to specifically stop barking at particular times. The only downside is that the owner needs to be there to operate it. Coverage is up to 600 feet.
I prefer the spray system for my Min Pins. They were always barking for anything that happened or anyone that walked by. Now they know something is going to happen if they do. I used to black bark collar just use a water spray when I was with them but that didn't work for long. Plus, I got tired of chasing them.
This should give you a great start on determining what system would be preferable for you and your dog. Just remember each pet is different and each will take different training methods to make them stop. Good Luck.