I have heard it said to get the Livestock charger for an electric fence. The ones for dogs won't contain a Pyr. I've heard this on several lists. But, I have no personal experience with this, as my dogs, for now, respect our fences. Barb Bowes Bo & Chelsea (Pyrs), Flopsy (Pyr Shep) & Machin (Doxie) The more people I meet, the more I like my dog! bamb@monmouth.com