Tilt n Turn windows and Tilt n Slide doors have gearing nearly all the way around the circumference of the opening window sash. The part of the gearing the handle goes in is called the drive gear locking mechanism, which consists of a gearbox connected to a long metal strip.
Drive gear locking mechanisms come in different size ranges and need to be cut down to the length of the original. The size range is usually printed into the long metal strip of the drive gear along with other letters and numbers. The size range will usually start FFH eg. FFH 601-1100.
Different makes of drive gear are rarely interchangeable because the drive gear has to link up to the rest of the gearing of the same brand.
The reason why most Drive gear locking mechanisms fail is because the window is out of adjustment. With Siegenia Gearing roller cams will appear around the circumference of the opening sash and can all be adjusted as required. The roller cams on a window need adjusting to increase compression on a slack window (symptom: handle goes into closed position too easily) or decrease window compression on an over tight window (symptom: handle has to be forced into closed position).