Our Manual Lawn Spike Aerator has four 3-inch spikes penetrate and loosen compacted soil. Spike aeration loosens soil and thatch to let air, water, and fertilizer down to the roots. Spike aeration also stimulates root growth by separating the roots. Your lawn will look better with less water and fertilizer. For best results water your yard thoroughly before aerating. Works well in rocky, highly compacted, root-bound or very sticky soil, such as due to high clay content. Yard Butler guarantees all Yard Butler tools for life against any defects in manufacturing or materials.