A solenoid for use with a fuel injector, the solenoid comprising a housing able to be attached to an injector; a core able to be located within the housing; a coil able to be located within the core; and an electrical cable electrically connected to the coil wherein at least the coil and the electrical cable connection to the coil is encapsulated by encapsulant. The reaction vessel including at least one upper opening with a seal element for reversible sealing for typical liquid handling techniques for filling, emptying mixing and gassing; at least one upper opening for pressure balancing and overrun; and a form stable body which forms at least one non capillary reaction cavity as an inner volume with at least one semipermeable membrane as a side wall. The rotor of said cylinder is connected to an actuating element by means of a front-side driving element wherein the actuating element is used to actuate main switching contacts associated with fixed contacts. In disclosed examples, a plurality of fillers are supported by a frame such that a first filler has a first width dimension and at least one second filler has a smaller width dimension.