This window looks like a traditional sash spring generally, but have more hidden advantages. This sash can be tilted up and down and also it can be tilted in for easy cleaning. In normal operation, sashes slide up and down as usual. However, the top of each sash can be tilted into the room to an angle of about 50-degrees, allowing simple access to the outer panes for cleaning. These kinds of windows are ideal for windows that are hard to reach from the building exterior, such as upstairs windows in built-up areas.