PetSafe Boundary Flags Use the 50 boundary flags to provide a visual reference when training your pet to learn the boundary Place the boundary flag in the ground every 10 feet near the warning zone When you are satisfied that your pet has mastered training, you may remove every other boundary flag every 4 days until all flags are removed Save boundary flags for future use Call, chat or email with our expert PetSafe US-based customer care specialists six days a week; They are waiting to assist you and your pet with your product needs PetSafe brand has been an industry leading US manufacturer of pet behavior, containment and lifestyle products since 1991, helping millions of people and pets each year