The Bark Buster "collar" is the universal check chain, the same sort that anyone can buy in a pet shop or any other general store that happens to sell pet products like leads and the like.
The first thing that we were taught by our Bark Busters trainer was to never ever leave a check chain on an unsupervised dog. This is because it is pretty easy for the dangling end of the check chain to get caught on something in the yard and as the dog panics to get free can cause itself a serious injury or worse. Our dogs only have the check chains on for walks, for training and for their APM dog wash time.
The other thing was to ensure that the dog saw the check chain as a sign of a good time with it's owner. If the dog rejected the check chain at any time then you had to go back to basics to reassure the dog that there was nothing bad about it. Lucky for us our older dog loves his check chain and gets really excited whenever we get it out as he knows we're probably going for a walk. Our younger dog is a little more reluctant but then she was an abused pup and has fear issues anyway. But she's getting alot better and at least doesn't run away or hide when we try to put hers on.
As for the barking issue - there are numerous reasons why dogs will bark and there are many solutions that Bark Busters offer. A good starting point is to try to identify the specific cause in your dog's case. Or if you already know then feel free to PM me and I'll see what our training guide recommends.