The standard OS Operator is non-handed and can be used for both casement and awning windows. It is 725 mm (28 ½” inches) long and includes a locking point at each end. For smaller windows, a handed, 466,5mm (18 ¾” inches) version with only 1 locking point is available.

How It Works:

• GIESSE’s innovative design begins with a cremone handle and mechanism that are mounted to the frame. The mechanism includes a movement arm, a gear to transfer movement, and attached locking pawls. Keepers are attached to an integral groove in the vent.


• At 0⁰, the window is closed and the locking points are secured. When the cremone is turned, the locking points release in the first 60⁰ of handle rotation. During the next 120⁰ of movement, the mechanism pushes the sash to the maximum opening based on the arm length. As the cremone rotates back to the closed position, the mechanism brings the event back to the frame and engages the locking points.