Vertical pivoting louvers protecting balcony 
It is a specially thought balcony. Besides the basic filter enclosure and the blinds for windows balcony access, the architect intended to create a second interesting space on the terrace. To do this, add a second filter, this time outside the balcony, over the rail. It is a filter for solar radiation, and to provide privacy and also for water tightness. This is a set of vertical slats which can be folded in two directions, they can also pivot vertically, allowing indirect sunlight.
In the picture we see what at first might seem a simple enclosure, but gets the facade to a certain variety. Once retracted, leave the gap completely open. While deployed, the space can become virtually airtight.
In the detail we also note the closure on the inner side of the terrace, the guide of the roller blind. Under the slats we can also see the guide, and we can deduce the deployment they can achieve.