Available in R-grids and PS-grids.
The special feature of R-grids is that the wire cranks are only applied onto one side in each wire position when compared to normal screens, so that one side of the finished screen is plain and the other cranked.
The typical feature of a PS-grid are straight wires which are crossed at right angles with the crossing points connected by pressure welding. This provides a wire position at the top and the bottom.
In general the wires at the top position are parallel to the material flow.