an apparatus for applying fluid to a substrate which is movable relative to the apparatus . a slotted nozzle assembly of the apparatus communicates with a fluid supply and includes an elongated slot with an outlet aperture . the length of the slot may be varied using a stopper which can move in the slot and seal it off laterally . in another aspect , the entire slot can be shifted and fixed in the direction of the longitudinal axis of the slot using a guiding and adjusting device .