Aeration helps keep the grass vibrant and healthy. Carburized steel tines penetrate the lawn removing up to 3" plugs of soil. Plug openings let water, seed and nutrients reach the lawn's root system and encourage the roots to spread and thicken for a fuller, lusher, healthier lawn. 28 plugging spoons are heat-treated for strength and durability. Weights added to the fully enclosed tray let you increase the penetration depth.