These should not be missing, especially in warm periods, when airing the houses is inevitable. In addition, it is the most effective and cheapest of all solutions against insects. They stop the penetration of insects and even dust.
For nets with a frame they can be: fixed or with hinges, the use of the latter being similar to that of windows, with the difference that they open outwards.

The roll-type nets (with vertical or horizontal operation) have the aluminum box and guides, so that the screen closes in a box, being visible only when it is lowered. Actioning is facilitated by a system of springs, raising and lowering is very easy, by pulling the actuation cord. During the cold season,
the net can be kept rolled up in the box, without having to remove it from the window. In both cases, the screen is made of glass fiber, resistant to precipitation, temperature changes and the action of the sun’s rays. The color of the screen is gray.

The color of the frames (in the case of the hinged ones) and of the guides and the box (for the roller type ones) is white or brown.