A bioelectric sensor device for sensing bioelectric data from a human body, the device comprising: a flexible dielectric substrate comprising a first major surface and a second major surface, wherein the substrate further comprises a sensor array portion comprising a center, a left reference electrode arm comprising a proximal end and a distal end, a right reference electrode arm comprising a proximal end and a distal end, and a contact array arm comprising a proximal end and a distal end, wherein the proximal end of the contact array arm is attached to the sensor array portion of the substrate; a plurality of sensors arranged in a sensor array on the sensor array portion of the substrate, wherein each sensor of the plurality of sensors is configured to sense bioelectric data when in contact with skin; an electrically conductive network located on the substrate, wherein the electrically conductive network comprises a plurality of electrically conductive paths, wherein each electrically conductive path of the plurality of electrically conductive paths extends from one sensor of the plurality of sensors to a contact array on the contact array arm, wherein the contact array comprises a plurality of contacts on the contact array arm proximate the distal end of the contact array arm; and a left reference electrode proximate the distal end of the left reference electrode arm and a right reference electrode proximate the distal end of the right reference electrode arm, wherein the left reference electrode is electrically connected to a contact in the contact array and the right reference electrode is electrically connected to a contact in the contact array; and characterised by a plurality of lines of weakness formed in the sensor array portion of the substrate, wherein each line of weakness of the plurality of lines of weakness is configured to enhance separation of the sensor array portion of the substrate along a separation line that extends between at least two sensors of the plurality of sensors to remove a sensor of the plurality of sensors from the bioelectric sensor device. a flexible dielectric substrate comprising a first major surface and a second major surface, wherein the substrate further comprises a sensor array portion comprising a center, a left reference electrode arm comprising a proximal end and a distal end, a right reference electrode arm comprising a proximal end and a distal end, and a contact array arm comprising a proximal end and a distal end, wherein the proximal end of the contact array arm is attached to the sensor array portion of the substrate; a plurality of sensors arranged in a sensor array on the sensor array portion of the substrate, wherein each sensor of the plurality of sensors is configured to sense bioelectric data when in contact with skin; an electrically conductive network located on the substrate, wherein the electrically conductive network comprises a plurality of electrically conductive paths, wherein each electrically conductive path of the plurality of electrically conductive paths extends from one sensor of the plurality of sensors to a contact array on the contact array arm, wherein the contact array comprises a plurality of contacts on the contact array arm proximate the distal end of the contact array arm; and a left reference electrode proximate the distal end of the left reference electrode arm and a right reference electrode proximate the distal end of the right reference electrode arm, wherein the left reference electrode is electrically connected to a contact in the contact array and the right reference electrode is electrically connected to a contact in the contact array; and characterised by a plurality of lines of weakness formed in the sensor array portion of the substrate, wherein each line of weakness of the plurality of lines of weakness is configured to enhance separation of the sensor array portion of the substrate along a separation line that extends between at least two sensors of the plurality of sensors to remove a sensor of the plurality of sensors from the bioelectric sensor device.