Looks like you are right about the Dogtra brand. Here is one on the Cabela's site that has great reviews and better yet, it's on sale!
http://www.cabelas.com/cabelas/en/templates/product/standard-item.jsp?_DARGS=/cabelas/en/common/catalog/item-link.jsp_A&_DAV=MainCatcat21404-cat601105-cat602223&id=0079074228651a&navCount=1&podId=0079074&parentId=cat602223&masterpathid=&navAction=push&catalogCode=OG&rid=&parentType=index&indexId=cat601233&hasJS=true
I figure we will end up having to get one for our lab pup (7 months) because she simply will NOT shut up, even in the house with lots of training to keep her quiet. No great improvements, but she is getting better.
dartonman - When you get one, would you mind posting what brand you got and what the results are? Much appreciated!