Out of site boundary fence system sets your dogs boundary.   To keeps them safe and out of trouble and harms way.  Giving your pet room to move freely within his safe home grounds.  Giving you the owner, the peace of mind you need. You can have multiply dog running off the same system you just need the extra DF-113R collars. Your dog does not need to be confined in a small area once it is trained with system he can have its own boundary fence. Your dogs will be able to enjoy a free range yard with “out of site boundary’s”. Your mind will be at rest knowing your dog is happy has boundaries and is safe from wandering. Fully dust and waterproof. This product uses low level ECT Comes with Warranty. Extra Receiver collars are available for purchase if you have more than one dog. Dog is safe to swim with collar. CAN PURCHASE A REMOTE TO ADD TO SYSTEM TO BECOME A TRAINER ALSO.