Casement windows operate by swinging panels inward and out, thus using a lightweight yet strong material such as aluminium is desirable as it assures users durability of not only the panels, but also the hinges which hold them. In addition, these windows offer great tightness when closed and hence are better resistant to air, sound and water inflow. The capacity to push or pull in the windows beyond the wall also allow users to enjoy a wider external view and amount of breeze when desired.