Abstract: Apparatus for gauging the thickness of moving laminar material comprising a gauging nip defined by a first roller of rigid material disposed on a fixed axis and a second roller biassed towards the first roller, the periphery of the second roller being rigid and adapted for movement away from the first roller, means for conveying the material through the nip and proximity detector means radially spaced from the periphery of the second roller and so positioned that the space formed therebetween is reduced upon the passage of material through the nip, the detector means being adapted to generate a material-thickness-indicative signal proportional to the displacement of the periphery of the second roller.