The Yard Butler Lawn Coring Aerator revitalizes old lawns while using less water and fertilizer. Old lawns can become compacted. Thatch from dead roots can also build up to create a thick barrier, keeping water and air from reaching the roots. By removing two 3-1/2 inch cores, the Lawn Coring Aerator reduces compaction and thatch to let air, water and fertilizer down to the root zone. At the same time it stimulates root growth by pruning the roots. Golf courses and baseball fields everywhere aerate their lawns. The heavy duty powder coated steel is guaranteed to last a lifetime.