Can anyone tell me where to get more info on TENS machines for Cat's / Dog's ?

I am a physio and use them on humans...but I didnt know you could get them for dogs. you'd likely have to shave a lot of coat for good electrode contact....and you tend to have to change the site frequently. I have to say my mind is boggling at the vision of a dog prepared to keep it on, let alone tolerate a tingling electric shock sensation! However for all I know the dog version may be different!
I shall keep an eye on the post with interest!

Must be a wind up surely.How would you explain to an animal that the electric shock is to distract them from the pain?I was ofered one of these in labour and lets just say-it didn't work!!!it just gave me more pain to wait for!and made me more P***** o**.