Block line of sight into private areas.
Giving adequate ventilation in areas where privacy must be maintained can be a challenge. NV1-3 non vision grilles have a special chevron blade arrangement, completely blocking line of sight through the grille.
The special chevron blade shape used on NV1, NV2 and NV3 grilles allows blades to interlock, completely blocking line of sight from any angle. NV4 grilles utilise a different, non chevron blade needed for the slimline construction. As a result a very narrow line of sight can be obtained by looking up at the grille from directly below.
Form however is just as important as function, and NV grilles have been designed to look as good as possible. NV1 - 3 grilles use the same style frames as the wider range of Air Precision grilles, for continuity across a range of grille types.