ROBOT MOWER PLUGS: ground spike to be inserted into the ground with hook to fix the boundary wire for robot mowers. You will receive 50 anchor pegs in a set. STABLE HEAD: The head of the anchor posts is so stable that it cannot break even when the cables are very tight. The anchor pegs are made of very stable plastic. EASY ATTACHMENT: The boundary wire only needs to be attached to the hook-shaped head of the anchor peg. The head is shaped so that the cable cannot slip. UNIVERSAL SIZE: Our anchor stakes are manufactured in one universal size. They fit all manufacturers. WEATHER RESISTANT AND DURABLE: The anchor pegs for the robotic lawnmower boundary wire are stable and weatherproof. They last for many years without having to be replaced. Ideal for a durable installation.