The easiest way to determine the handing of your casement window unit is from the INTERIOR (inside) of the home. If you have multiple windows, stand in front of each window in question and locate the locks. The lock location will determine the handing of the unit.
All casement hardware, which includes locks, operators and hinges, are handed based on the lock location when viewed from the interior.
Alternatively, handing can also be determined by the hinge side when viewed from the EXTERIOR.
Examine the product image carefully when ordering. You should be able to see the difference between the left and right-hand side version.