Unique Hollow blade design by GST is something you will never find elsewhere. The hollow veil in the center of the grass leaves makes up not only for truly outstanding realistic look of grass, but supports its quality to keep temperature of a lawn stable and cool in hot climates. In plants, leaf surfaces are dotted with stomata (openings, or holes) bordered by guard cells that open and close the pore. Transpiration which cools plants occurs through the stomatal apertures. Transpiration serves to evaporatively cool grass as the escaping water vapor carries away heat energy. Hollow blade technology mimics the same process which helps to keep moisture inside stems longer and therefore to lessen the temperature of a lawn.