Grator Flip-flow mats are made from an engineering polymer which has extremely low moisture absorption and has a very low co-efficient of friction. These mats are designed to break or loosen the adhesive bond between the different materials during screening operations. The flexible mat provides flexing and relaxing operation there by aperture elongated and stretch or bend which helps in discharging materials. Mats can be used for classification of intermediate and fine/coarse materials.