Device used to remove large solids particles such as fiber bundles and flakes from stock. In good old days screen used to be open type and could deal with thin stock only. Modern screen are closed (pressurized) and can handle low, medium and even high consistency stock. Perforation in screen basket can be circular, counter shrink or slotted. The screen used just before headbox not only remove large particles but also align fibers in the direction of stock flow.