Casement Handing

Operating, or venting, casement windows are considered left-hand or right-hand, depending on the position of the hinge as viewed from the exterior of the window:

In many cases, the parts applied to a casement are specific to its handing. For example, all Eagle operators are either left- or right-hand, depending on the handedness of the window for which you are replacing the part. Lock bars, however, work on either type of operating casement.

It may also be illustrative to examine the window from the interior, as in this diagram. A left-hand casement typically has the operator handle and hinge(s) on the right and the lock handle on the left, when viewed from the inside. A right-hand casement has these items in the opposite locations.