Window crank

Hello there. We may be able to help, but I need to see the entire assembly, including the arm(s) that come out of that back of that gear box and control the window movement. A bird's eye view, with either the operator removed from the window or at least with the window open, would be best. We should be able to narrow this down from there. 

Thanks! This looks like it could be a match for either our 39-438B or 39-253LB, depending on the design of the guide at the end of the arm. The video below will clarify precisely what I mean and will allow you to select the proper replacement part.

Can you verify those product codes? The 39-375 is a cover/handle kit, but the 39-531 is a sash bracket. These serve very different roles.

Ah gotcha, thanks for clarifying! In that case, no there's no mechanical difference between the 39-375 and 39-451 other than the fact that the 39-375 has a folding handle and the 39-451 doesn't. Besides that, they work the same way on the same kind of operator, but they just offer two different aesthetic styles. Choosing between them is just a matter of your own personal tastes.