Unless you want to spend $25 for the instructional dvd that comes with the tell bell, you should do a search on ebay, etc.
You can find "service" bells that will ring just fine for much, much less money. There is also a wealth of information available online regarding bell training. I would check around first and see what you can find for free before spending alot of money on the tell bell DVD.
You might even be able to find a service counter type bell at your local big-box office supply stores.
If you are interested in training your dog more extensively beyond a potty bell, it may be time to invest in a good dog training book that utilizes positive reinforcement methods.
Good luck with your search!
