where to buy runner/walkers self defense items?

[stargirl]

Its been ages since I've posted, I hope I've got the right forum. I'm a weekend runner and need to find something to take with me to repel stray or pet dogs which occasionally chase or follow me. I do not want to hurt the animals but truly fear them (sorry, dog lovers). Isn't there some kind of sonic device or something like that? Also to take something that I could use in self defense against the animal if it attempted to bite. Or any other ideas and where to purchase it would be appreciated.