these can only work by either scaring your dog, or teaching your dog these are unpleasant. Why would you do either? Much simpler and nicer to teach your dog what you want rather than being something your dog becomes scared of.
As the owner of Olantigh Dog Training we use these discs all the time on some dogs that have behavioural issues. If introduced correctly with my methods they work brilliantly
I tried everything on the market from pet corrector sprays, stones in a tin, whistle, treats, lead control etc., to try to calm our very excitable dog down, stop him pulling on a lead and stop him jumping up at visitors. These training discs really do work and so simple to use. I can highly recommend these and especially for the price. There're brilliant.
My dog listens to these disks as if they were the only thing in the world that is interesting. just brilliant.