The SportDOG Brand® Contain + Train system allows you to contain your dog in the boundary that you define and train your dog inside or outside of the containment area without having to switch collars. The Collar Receiver fits any dog 10 pounds or larger, and works with our In-Ground Fence (SDF-100A) transmitter to contain your dog in up to 1 1/3 acres of land with the included 1, 000 feet of wire or up to 100 acres with the purchase of additional Wire & Flag Kits (SDF-WF). The included Remote Trainer from our FieldTrainer® 425 (SD-425) communicates with that same Collar Receiver up to 500 yards away and gives you the capability to train with your choice of tone, vibration, or static stimulation. Training mode expands to 3 dogs & Containment mode expands to any number of dogs with Add-A-Dog® Collar Receivers Includes 1, 000 feet of wire & 100 boundary flags to cover 1 1/3 acres; Expands to 100 acres with extra Wire & Flag Kits Collar Receiver is waterproof & submersible to 10 feet | PetSafe SportDOG Brand ® Contain + Train System