I highly recommend PetSafe wireless fence. However, you can check some other companies as well before buying one. Check on oodlelife.com You can find some excellent tips regarding dog fences and dog products in general.
The most important thing is not to save some money and buy a cheap item that won't last long. Consider buying something made of high quality materials. However, I am not really into wireless dog fences since the noise of the collar might not be the nices one. And even if I recommended one already, you still have to know that it was used only for a short period. It's up to you!
