KMLabs filter wheels are extremely useful accessories for the XUUS eXtreme Ultraviolet Ultrafast Source:

•  Each wheel includes four apertures which can be rotated into the beam path
   downstream from the capillary
•  One aperture allows gas flow when pumping down and venting the vacuum
   system without the risk of break the thin filters.
•  The other three apertures allow for mounting thin film filters of varying
    thickness and composition
•  Can be used to optimize the ratio of EUV transmission/ IR block for different
   EUV wavelengths
•  Can be used to calibrate measurements of the EUV flux
•  Two filter wheels with two metal filters in series with offset pinholes are optimal
   for preventing holes in a single metal plate from transmitting IR light