The invention provides novel slot tube screen material for filtering applications, in particular for separating solid particles from liquids. The slot tube filter screens manufactured according to the invention feature very small slot openings, which are narrowed with respect to a slot opening dimension of conventionally fabricated slot filter tubes. The slot tube construction of the invention comprises a torsion-rotation deformed structure of normally axially orientated parallel support members of the slot tube mantle, which further comprises spiral windings of profile wire around said support members, whereby at each contact crossing a solid weld connection fixes a crossing profile wire to a support member. The plastically twisted slot tube structure displays a helical distortion of the axial support ribs inside the slot tube. As a consequence the filter slot openings between adjoining windings of profile wire are markedly narrowed (versus undeformed slot tube), which offers the possibility of reliably achieving very small filter slot openings of less than 0.020 mm in slot tube filters or screens.