The Premier Pet Wireless Add-A-Dog collar allows you to expand your current Premier Pet Wireless Fence (GIF00-16917 or GIF00-16347) or the Guardian Wireless Fence to contain an unlimited number of dogs, or can be used as a replacement or extra receiver collar. When used with any of these wireless fence systems, a circular barrier keeps your dog safely in your yard. Coverage is adjustable up to 1/2 acre and is expandable for additional coverage area. This waterproof receiver collar is adjustable up to 27", making it a great fit for both smaller and larger dogs. A low battery indicator on the collar will alert you when the collar battery (GAC11-16351) should be replaced. The collar has 1 level of tone only for training and 5 adjustable levels of static correction so that you are able to choose which level works best for your dog. A safety time-out feature will stop correcting after 30 seconds should your dog get outside of the boundary zone. Give all of your dogs freedom to play and yourself peace of mind with the Premier Pet Wireless Add-A-Dog!