Stop worrying about buying a new fence system and get an extra collar to extend your pets containment system. Now whether you are replacing an old beat-collar or just got a new pet you know they will be safe in your yard. This receiver/collar is designed for the SD-2100 and SD-2200 pet containment systems. The collar is recommended for dogs 10 lbs and up. It is fully waterproof, reflective and rechargeable using quick-charge NiMH batterie.