12c-is23 interlock

Thanks for posting. If it's the window hinge you're looking for (the arms that keep the window stable as it opens and closes, rather than anything directly attached to the casement operator, or the part with the crank handle), then I believe we may be able to help. This exact hinge is no longer made, but our 36-048 might be able to do the trick, so long as you replace both hinges in the window. Compare the dimensions below with your old hinge and see if you think you could get this to fit your window. 

Detail of 36-048

Additional dimensions for 36-048