I bike in areas that have no leash laws and so encounter dogs with some frequency. I would like something to inhibit them that would be easy to access and use. Someone lent me a Dazzer. Here is the Amazon promo:
https://www.amazon.com/Dazer-36269920...8432952&sr=8-1
It has a belt clip that could go on a belt or cable without any modification. Do they work with aggressive dogs especially at a distance?

I've never heard of it, but I see there is a BUNCH of reviews on Amazon, read through a few of those.

I have a similar device that claims to repel mosquitoes with an inadible sound that humans can't hear. It gave, if anything, the mosquitoes the munchies!

Caveat Emptor.

just get a tazer, that'll make the dog think twice. or better yet, the next mutt that chases you down, go to the owner and tell him to leash it or face a lawsuit the NEXT time you get bit (yeah, you may not have actually gotten biten, but it kinda helps make the point if you make it sound like u did)

Tazers are the ones that shoot out something that attaches to you. Stun guns are better but you still have to be close enough to touch them. After I was attacked by a pittbull walking my dog I always carry a stun gun. I have found that when a dog is comming at you if you hit the button a couple times the sound of the stun gun stopped the dog in it's tracks. If it doesn't and you have to zap them, the next time they hear that sound they will definately think twice about comming toward you.