Left and right gear box for Pella windows

Hello, thank you for posting,

To further review, it would be best to see the screen removed where we can see an unobstructed view of the crank operator arm to further confirm. 

At first sight, your crank resembles the 39-175 and 39-176 Pella operators. Please review the overall dimensions and style below to confirm a good fit! Let us know what you think! Also see the 39-109B for a compatible handle. Please note that the cover has been discontinued. 

Dimensions for 39-175

View of the arm of the 39-175 window operator.