Abstract: Illustrated is a cartridge type solenoid valve with a coil-actuator structure which employs O-ring seals to inhibit harsh environment entry into the coil-actuator and allows for metal to metal contact with the frame to increase the flux density and path for flux when the valve is in operation. A plastic over mould is encapsulated over the metal frame (in one embodiment a sleeve) which is shaped to provide efficient magnetic flux carrying capability, as well as abut a flux connector, e.g. a disc adapted to capture an O-ring. The O-ring is in sealing contact with a capture element, e.g. a nut on the projecting extended end of an insertable cartridge having an internal plug, environmentally sealing the coil. When the capture nut is assembled on to the plug, in sealing engagement with the O-ring and simultaneously engaging the plug, an increased efficiency flux path is created. The lead wire termination version includes cold forming or latched caps over lead wires to provide environmental (or dunk) sealing.