Apparatus and method for control of epitaxial growth parameters, for example during manufacture of light emitting diodes. The magnet is moveable so that the direction of the magnetic field lines in the operating region is adjustable. The casing covers interact with a electrode cover assembly underneath the casing covers, that allows the lamp to be inserted when the casing covers are opened. A fastener is adapted for attaching the second end to the front side of the panel. Convert the detected set of second touch coordinates into a set of first corrected coordinates. The connection mechanism may include electrical connections between the components.