Abstract: An improvement to an electro-magnetically actuated piston has a first magnetic core and a second magnetic core. There is an electro-magnet coil for magnetically coupling the first and the second magnetic cores. The coil moves the first and second magnetic cores relatively, one to another. In the improvement itself the first and the second magnetic cores each comprise non-conductive core material or an array of a multiplicity of lamination plates. The non-conductive core material or each of the lamination plates are configured to receive a portion of the electro-magnet coil. The nonconductive core material or array of lamination plates encloses the coil and contains the magnetic field produced by the coil when the coil is energized. When the non-conductive core material or lamination plates of the first and second magnetic cores are in juxtaposition, the result is to generally isolate any magnetic materials adjacent the lamination plates from the magnetic flux produced when the coil is energized.