The product line-up of NAROO MASK is quite easy to understand. It is made up of combinations of three elements:
1) Mask category: Z, F, N, X, E.
2) The thickness of the fabric: 1, 3, 5, 7, 9.
3) Type / length of the mask:
S for Short,
H for half-face,
F for full-face,
and the absence of the letter means the usual length of the mask that covers the neck.
For instance, Z5H means it is a model of Z (Advanced) category with a thickness of 5 points and Half-balaclava style