The Diffraction Apparatus (DAK) includes slits and lasers. The slit dimensions and laser wavelengths are critical dimensions for comparing experimental results with theory.
The tolerance of slit widths and separations is 3-4 microns.
The laser wavelengths are
green 532 +/- 1 nm
red 635 +/- 5 nm
Both lasers are Class 2 laser products.