The PetSafe Cat Fence Collar works with the PetSafe Underground Electric Cat Fence and the PetSafe Indoor Cat Barrier The specially designed Cat Safety Collar features Nylon web construction with an elastic safety strip that will stretch in those instances where your cat is exploring in a tight place. With the PetSafe Cat Fence Collar you can increase or decrease the correction to meet your cat's training needs. The PetSafe Cat Fence Collar allows you to contain as many cats as you like within the same fence. The collar is light and durable - perfect for a older or smaller cat, and when set at a correction level 4, strong enough for the largest and most stubborn cat. The PetSafe Cat Fence Collar uses the RFA-188 3 Volt Battery. PetSafe Cat Fence Collar Features: Our smallest waterproof receiver collar 4 levels of correction, plus tone-only Good- and Low-battery indicator Stretch-section on collar for cats safety Owners Manual