This extra receiver collar can be used to add another dog or as a replacement collar to the Stay & Play® Wireless Fence with Replaceable Battery Collar, Stay & Play® Compact Wireless Fence, or the Wireless Pet Containment System. This Stay & Play® Wireless Fence Replaceable Battery Receiver Collar includes 5 levels of static correction plus tone only adjustable to your pet's temperament. Features Add Unlimited Pets to Your System - Keep as many pets as you need safely in your yard as long as they wear a PetSafe® Wireless Fence Receiver Collar (Not compatible with PetSafe® In-Ground Fences) Waterproof Receiver Collar - for all of your pet's outdoor activities 5 Levels of Static Correction - Customize to your pet's temperament. Also has a tone only mode for training. Slim, Ergonomic Design - Fits pets 5 pounds or more with neck sizes 6 to 28 inches Short and Long Contact Points Included - For pets with long or short hair Battery Included - Uses RFA-67 battery module with 1-2 months of expected battery life New Name, Same Product You'll Love - Formerly known as the Free to Roam Wireless Fence™ Receiver Collar Safe, Effective, Trusted - Our training collars are part of our ongoing mission to provide the best tools, education and support for pet parents seeking safe, successful, expert-recommended options to meet each dog’s unique training needs