The ABUS FAS101 additional lock is intended for securing the hinge side of a window. You should secure the opening side separately. When you open the window, the FAS101 simply moves with it; in order to tilt the window you must first unlock the security bolt. Then, once the window is in the tilted position, push the bolt back in. The hinge side lock is mounted on the casement and on the frame. Thanks to its narrow design the FAS101 can be used where installation space is tight.