M42x1 Aperture diaphragm

max. aperture diameter: appro 25mm
min. aperture diameter: appro 1mm
approximate outer casing dimensions:
  outside diameter: 54mm
  thickness: 13mm (w/o male M42 thread);
          17mm (w/ male M42x1mm thread)
Diaphragm blade count: 14
Outer casing (male and female threads) do not turn
when opening or closing the diaphragm.