Concrete Donuts for a Rotary Head Full, Large Full, Green Protects the Heads from Mowers Edgers Landscapers and Teenage Drivers Displaces the Weight of a Vehicles Tire Aiding in the Prevention of Broken Heads and Pipes The Concrete is impregnated with Fiber for additional strength and the entire mixture is dyed green to blend with the Grass Water Loss Prevention It aids in the prevention of the breaking of Sprinkler Heads and Pipe The Donut is produced using the most advanced technology in Concrete mixture combinations for strength and freeze resistance