truth rear mount single arm operator

Thanks for your post! There is a chance w we can provide you with the a replacement for recommendation. May I see a photo of the entire operator? We'll need to see a photo of the base and the entire arm.

Please let me know if you have any questions.

Thanks for the additional photos. Take a look at the 39-701 Rear Mount Casement Operator. The opposite version of this operator is the 39-700.

If you also need the handle, take a look at the 39-114L Crank Handle. Another option is the 39-205 folding handle.

Dimensions for 39-701

Dimensions for 39-701

We can no longer get the 11" arm through our suppliers, so we aren't sure it is available any longer. That being said, the 9-1/2" arm should still work in your window. 

You might need to move the location of the track on the sash, but it is suggested to try it out first the to see if it creates an issue. 

As for the mounting screw we do carry the 33-083, but not sure what type head screw you need; a pan head vs a flat head. I'm also not sure of the length you need for your window. It's best to reuse your existing screws or purchase new screws at a hardware store in your area.