ADD UNLIMITED PETS TO YOUR SYSTEM: Keep as many pets as you need safely in your yard with this add-a-dog receiver collar. Compatible with all PetSafeIn-Ground Systems except YardMax and UltraSmart. 4 LEVELS OF CORRECTION: Plus tone-only mode for training. Pets can be trained in 2 weeks when used as directed WATERPROOF RECEIVER COLLAR: With low battery indicator ADJUSTABLE RECEIVER COLLAR: Fits pets 8 lb or more with neck sizes 6 to 26 inches SHORT AND LONG CONTACT POINTS INCLUDED: For pets with long or short hair