Casement style windows are attached to the frame by one or more hinges and can have upwards of five to six sashes (the moveable parts of the window). Typically, they open and shut by means of crank located at the bottom of the frame. When closed, locking mechanisms on the frame pull the sash up against the frame and lock it tightly in position. These windows can be hinged to open outward or inward and are excellent for natural ventilation