An assembly of a neuromodulation electrode comprising: an enclosure having on one side a removeable protrusion extending up to an end having an opening, wherein the removeable protrusion is selected from a plurality of removeable protrusions having different diameters of the opening; an electrical interface adapted to be coupled to an external apparatus; an electro conductive electrode piece coupled to the electrical interface on one end and having the opposite end configured to interact with a patient skin via a portion of the electrode piece that projects outwards through the opening, the electrode piece comprising: an electrically conductive solid element (16, 15) coupled on one side to the electrical interface; and an electrically conductive soft deformable element (7, 14) that projects outwards through the opening and which is adapted to form an interface between the solid element and the patient skin, wherein the conductive soft deformable element is at least partially hollow and the electrically conductive solid element is received within the conductive soft deformable element, wherein the selection of the removeable protrusion having a particular diameter size of the opening controls how far the electrically conductive soft deformable element projects outwards through the opening. an enclosure having on one side a removeable protrusion extending up to an end having an opening, wherein the removeable protrusion is selected from a plurality of removeable protrusions having different diameters of the opening; an electrical interface adapted to be coupled to an external apparatus; an electro conductive electrode piece coupled to the electrical interface on one end and having the opposite end configured to interact with a patient skin via a portion of the electrode piece that projects outwards through the opening, the electrode piece comprising: an electrically conductive solid element (16, 15) coupled on one side to the electrical interface; and an electrically conductive soft deformable element (7, 14) that projects outwards through the opening and which is adapted to form an interface between the solid element and the patient skin, wherein the conductive soft deformable element is at least partially hollow and the electrically conductive solid element is received within the conductive soft deformable element, wherein the selection of the removeable protrusion having a particular diameter size of the opening controls how far the electrically conductive soft deformable element projects outwards through the opening. an electrically conductive solid element (16, 15) coupled on one side to the electrical interface; and an electrically conductive soft deformable element (7, 14) that projects outwards through the opening and which is adapted to form an interface between the solid element and the patient skin, wherein the conductive soft deformable element is at least partially hollow and the electrically conductive solid element is received within the conductive soft deformable element, wherein the selection of the removeable protrusion having a particular diameter size of the opening controls how far the electrically conductive soft deformable element projects outwards through the opening.