Asymmetric DualFan Nozzles for Colorants, Dyes and Pigments Greenleaf Asymmetric DualFan Nozzles can be used on self-propelled sprayers and walking booms to apply colorants, dyes and pigments to turf. The unique pattern provides front and back coverage of the leaf blade, which can be further enhanced by alternating every other nozzle on the boom. Medium sized droplets are recommended.