Light curtain device (10, 20) comprising one or more light emitting elements for generating a light curtain, wherein - the light curtain device (10, 20) comprises a housing for accommodating the one or more light emitting elements and a first and a second opening (31, 32) at opposing end sections of the housing, - wherein a terminal cap (11, 12) and an internal gasket are mounted at at least one of the openings (31, 32) of the housing, the internal gasket being mounted between the terminal cap (11, 12) and the housing and sealing the interface between the terminal cap (11, 12) and the housing in an airtight manner to prevent fluids from entering the interior of the housing at the interface between the terminal cap (11, 12) and the housing, - wherein the terminal cap (11, 12) comprises electrical contact elements (40, 41) that each have an internal end that is connected to one or more electrical components located inside the housing, and an external end which allows connecting the electrical contact element (40, 41) to a corresponding electrical contact element (40, 41) of a another light curtain device (10, 20), - wherein the electrical contact elements (40, 41) extend along the terminal cap (11, 12) and pass the internal gasket, and - wherein at least one squeezing element provides a squeezing force onto the internal gasket, characterized in that - the terminal cap (11, 12) provides at least one locking hook for engaging with a locking recess of the other light curtain device (10, 20), and/or at least one locking recess for engaging with a locking hook of the other light curtain device (10, 20) in order to provide a form-fit connection with the other light curtain device (10, 20), wherein the form-fit connection is configured to provide a mechanical force that presses the terminal caps (11, 12) of the light curtain devices (10, 20) together, - wherein the outer surface of the terminal cap (11, 12) is configured to be provided with an intermediate gasket that is pressed in response to the form-fit connection and seals the interface between the terminal caps (11, 12) of the light curtain devices (10, 20), - wherein the intermediate gasket surrounds and seals the external ends of the connected electrical contact elements in an airtight manner to prevent fluids from reaching the external ends of the electrical contact elements. - the light curtain device (10, 20) comprises a housing for accommodating the one or more light emitting elements and a first and a second opening (31, 32) at opposing end sections of the housing, - wherein a terminal cap (11, 12) and an internal gasket are mounted at at least one of the openings (31, 32) of the housing, the internal gasket being mounted between the terminal cap (11, 12) and the housing and sealing the interface between the terminal cap (11, 12) and the housing in an airtight manner to prevent fluids from entering the interior of the housing at the interface between the terminal cap (11, 12) and the housing, - wherein the terminal cap (11, 12) comprises electrical contact elements (40, 41) that each have an internal end that is connected to one or more electrical components located inside the housing, and an external end which allows connecting the electrical contact element (40, 41) to a corresponding electrical contact element (40, 41) of a another light curtain device (10, 20), - wherein the electrical contact elements (40, 41) extend along the terminal cap (11, 12) and pass the internal gasket, and - wherein at least one squeezing element provides a squeezing force onto the internal gasket, characterized in that - the terminal cap (11, 12) provides at least one locking hook for engaging with a locking recess of the other light curtain device (10, 20), and/or at least one locking recess for engaging with a locking hook of the other light curtain device (10, 20) in order to provide a form-fit connection with the other light curtain device (10, 20), wherein the form-fit connection is configured to provide a mechanical force that presses the terminal caps (11, 12) of the light curtain devices (10, 20) together, - wherein the outer surface of the terminal cap (11, 12) is configured to be provided with an intermediate gasket that is pressed in response to the form-fit connection and seals the interface between the terminal caps (11, 12) of the light curtain devices (10, 20), - wherein the intermediate gasket surrounds and seals the external ends of the connected electrical contact elements in an airtight manner to prevent fluids from reaching the external ends of the electrical contact elements.