6C005"Laser" materials as follows:

a. Synthetic crystalline "laser" host material in unfinished form as follows:
1. Titanium doped sapphire;
2. Not used.
b. Rare-earth-metal doped double-clad fibres having any of the following:
1. Nominal "laser" wavelength of 975 nm to 1 150 nm and having all of the following:
a. Average core diameter equal to or greater than 25 μm; and
b. Core 'Numerical Aperture' ('NA') less than 0,065; or
Note:
6C005.b.1. does not control double-clad fibres having an inner glass cladding diameter exceeding 150 μm and not exceeding 300 μm.
2. Nominal "laser" wavelength exceeding 1 530 nm and having all of the following:
a. Average core diameter equal to or greater than 20 μm; and
b. Core 'Numerical Aperture' ('NA') less than 0,1.
Note:
6C005.b. includes fibres assembled with end caps.
Technical Note:
For the purposes of 6C005.b., the core 'Numerical Aperture' ('NA') is measured at the emission wavelengths of the fibre.