An electrode and enclosure for a medical monitoring or therapy instrument comprising: an enclosure formed of a substantially rigid, moisture impervious material and having an inner surface against which one or more electrodes maybe sealed; and an electrode having a substantially moisture-impervious outer layer and a hydrophilic inner layer, the outer layer being peripherally sealed to the inner surface of the enclosure prior to use; and a closing device which retains the enclosure in a closed state prior to use of the electrode, characterized in that a second electrode has a substantially moisture-impervious outer layer and a hydrophilic inner layer, the outer layer being peripherally sealed to the inner surface of the enclosure prior to use, wherein the enclosure further comprises first and second halves (23, 24), each having an electrode release surface (25, 26), wherein an electrode is sealed to each of the release surfaces (25, 26), and - conductive elements (35, 36) disposed on the release surfaces (25, 26), the conductive elements (35, 36) providing a conductive surface within the respective release surface (25, 26), characterised by a conductive path from a release surface (25, 26) to a respective connector (37, 38) located at the periphery of the enclosure, wherein respective connectors (37, 38) on conductive elements (35, 36) are configured to mate when the enclosure is closed providing a conductive path from the first release surface to a second release surface. an enclosure formed of a substantially rigid, moisture impervious material and having an inner surface against which one or more electrodes maybe sealed; and an electrode having a substantially moisture-impervious outer layer and a hydrophilic inner layer, the outer layer being peripherally sealed to the inner surface of the enclosure prior to use; and a closing device which retains the enclosure in a closed state prior to use of the electrode, characterized in that a second electrode has a substantially moisture-impervious outer layer and a hydrophilic inner layer, the outer layer being peripherally sealed to the inner surface of the enclosure prior to use, wherein the enclosure further comprises first and second halves (23, 24), each having an electrode release surface (25, 26), wherein an electrode is sealed to each of the release surfaces (25, 26), and - conductive elements (35, 36) disposed on the release surfaces (25, 26), the conductive elements (35, 36) providing a conductive surface within the respective release surface (25, 26), characterised by a conductive path from a release surface (25, 26) to a respective connector (37, 38) located at the periphery of the enclosure, wherein respective connectors (37, 38) on conductive elements (35, 36) are configured to mate when the enclosure is closed providing a conductive path from the first release surface to a second release surface. - conductive elements (35, 36) disposed on the release surfaces (25, 26), the conductive elements (35, 36) providing a conductive surface within the respective release surface (25, 26), characterised by a conductive path from a release surface (25, 26) to a respective connector (37, 38) located at the periphery of the enclosure, wherein respective connectors (37, 38) on conductive elements (35, 36) are configured to mate when the enclosure is closed providing a conductive path from the first release surface to a second release surface.