Extra boundary flags for training your pet to use an in-ground or wireless fence. Place flags approximately 10 feet apart to remind your pet of his off-limits area. Between days 15 and 30, you will be monitoring your pet's progress. After you are satisfied your pet's training is complete, remove every other Boundary Flag every 4 days until all flags are removed. In about a month, your lawn will be free of training flags and your pet will know his limits. We recommend keeping a flag or two in your yard to let neighbors and passerby know that your pet is securely contained. Trust PetSafe® to help keep your pet healthy, safe and happy.