The SPI Supplies apertures, be they drilled Pt or Mo or of the gold foil thin firm type, are all made to the most exacting of standards and with the smallest possible tolerances, not just in hole size, but also placement.
ZEISS® / LEO® - 2mm O.D. x 0.1mm thick and 10mm O.D. x 0.1mm thick and 12mm O.D. x 0.1mm thick