Surfactants reduce the surface tension of the carrier solution, therefore improving retention and coverage of the aqueous spray droplet on the leaf surface. Leaves of all plants are covered with a waxy structure known as the cuticle. Surfactants reduce herbicide losses caused by spray droplets bouncing or rolling off the leaf surface, much like rain rolls off the hood of a newly waxed car. Surfactants also increase the rate at which a herbicide is absorbed into the leaf. Surfactants typically are used at rates from 0.125 to 0.5% of the carrier volume.