dual arm operator

Question

I have these photos. I need to replace the part that opens and closes the window. I can open but I cannot close. The units are about 20 years old

It seems that the round part with the teeth is worn out

Bob · Accepted Answer

Thanks for posting. This looks like either a 39-253RB or 39-439B Dual-Arm Operator. These operators are nearly identical, except for the appendage used at the end of the straight arms. The video below explains more. In either case, for a new cover and handle use either the 39-376 or 39-452, depending on the style you prefer.