Grass is a living thing that needs air and water to grow. Regular mowing and other outdoor activities in the garden during the summer months lead to compaction in the surface layer of the lawn. Drainage is impeded and it is harder for water , air and fertiliser to penetrate to the roots. The Greenkey lawn aerating sandals provide a fast and efficient way to keep your lawn aerated, helping the lawn to breathe and take in essential nutrients. The thirteen 50mm (2") spikes on each shoe provide deep and even aeration. Best used as part of your lawn care routine in Spring and Autumn. For best results, use when the ground is soft. Do not use on stoney or uneven ground Very quick to assemble. Spare parts available.