Looking for a replacement part

This looks possibly like a surface lever for an internal tilt latch, such as our selection here. A possible replacement is determined by the length of those prongs, as well as the distance between them. If none of our surface levers have the same dimensions, then there may be no replacement, and you'll have to consider converting to surface-mount tilt latches like our 26-228 and 26-229. The video below shows how to do this.