A device for the treatment of strand-shaped textiles includes a treatment container, a transport nozzle array, and a transport path by way of which a material strand can be moved through the transport nozzle array in a transport direction. The transport nozzle array includes a transport nozzle with nozzle inlet and outlet orifices for the material strand, between which are delimited at least two nozzle gaps for a transport medium. At least one of the nozzle gaps is adjustable regarding its gap width. At least one nozzle gap can convey the material strand in the transport direction, and at least one nozzle gap can convey the material strand in a direction counter to the transport direction. The device also includes a control unit that selectively drives the material strand in the transport direction or in the direction counter to the transport direction by appropriate actuation of the nozzle gaps.