A combination of a defibrillator and an electrode package, the combination comprising a defibrillator comprising electrical output wires for delivering a defibrillation pulse to defibrillation electrodes, processing circuitry and associated software for controlling the delivery of the defibrillation pulse, an electrical energy storage element for storing the energy delivered in the defibrillation pulse, a user interface element or elements connected to the processing circuitry for accepting one or more inputs from the user and communicating one or more pieces of information to the user, a housing containing the storage element, processing circuitry, and user interface, and a first mechanical element or elements on the exterior of the housing and configured so that an electrode package can be mechanically attached to the exterior of the housing substantially in full view on the exterior, and an electrode package containing the defibrillation electrodes, the package comprising an outer shell, a portion of the outer shell configured to be opened to remove the electrodes, two or more defibrillation electrodes sealed inside the electrode package, and a second mechanical element or elements on the exterior of the outer shell and configured to mate with the first mechanical element on the housing of the defibrillator to mechanically attach the package to the housing.