"I am interested in a taser for protection from bears as we do a lot of walking in bear country. To this end we have two questions: Are your devices effective against bears? Are Tasers legal in Canada as much of our RV'ing in the summer is in Canada?" - Bonnie B.
That's quite a popular question and it has a funny answer, but it really depends upon the bear! Joking aside, they are not designed for use against bears. IF you have one and get attacked by a bear, then you can use it. The problem is that a bear's fur is very thick and so the probes my or may not make good contact with the bear's skin. You can still use the stun gun to his face, nose, mouth etc, but that is way too close for my liking. Finally, Tasers are not legal in Canada and cannot be exported outside the US.
A better option would be the Frontiersman Bear Attack Deterrent with Belt Holster (on sale at $51.99). That has a range of 35 feet and it's super-strong formulation is specifically designed for deterring bears. Whilst correctly labeled bear spray (not pepper spray) is legal in Canada, there are some requirements about crossing the border with it that are explained in this excellent article.
I hope that helps.