PetSafe's newest offering in pet containment fences is this Deluxe little dog fence designed for dogs from 8 to 25 pounds. With the all new PetSafe deluxe dog fence transmitter and state of the art little dog 5 level receiver collar, this is one of the best electronic pet containment fences ever built. The little dog pet containment fence features the QuickFit buckle and provides a quick release and a perfect fit every time. Includes a durable, deluxe 5 level 100% waterproof Receiver Collar. PetSafe is the world's Best Selling Pet Containment System and includes a one year Limited Warranty. Safe and Effective for all little dogs from 8 to 25 lb. The pet containment fence works by delivering mild Static Correction through two Contact Points that touch your little dogs neck. With this PetSafe containment fence you can contain dogs of all sizes within the same fence. You may add as many receivers for dogs (large or small) or even cats as long as they are made by PetSafe. One additional receiver is required for each pet you wish to contain. Once your pet has learned the boundary of the yard, it will only receive a static correction when nearing the boundary. The initial 500 ft of 20 gauge underground wire wire allow you to cover approximately 1/4 acres of land, but with additional boundary wire Kits the fence can expand to cover up to 25 acres. The PetSafe little dog containment fence allows you to install the fence in almost any size or shape, independent from any slopes your yard might have.