A quick learner from Bonita Springs, Fl. says:
March 5, 2012
This window crank is for a jealosy window. It has 3 screws holding it to the frame and has a 2 1/2" link
Donna from SWISCO responded:
March 7, 2012
SWISCO product code 39-258, awning window operator, looks very similar to your original operator. Please compare the measurements and let us know what you think.