Vertical slider windows are a type of window that works great when the opening is taller than it is wide. This is called the golden ratio, which is 1:1.618. These windows are also great when you only need one part of the window to open for ventilation or in case of a fire. 

So, if you need a window that is taller than it is wide and only need one part of it to open, a vertical slider window might be the perfect choice for you!