Truth crank window

This window operator has a similar design to both the 39-253LB and 39-438B Encore Dual Arm Operators. To determine which of these is the correct operator, you'll need to compare the differences between them and the accessories they use; please see the video tutorial below for reference. Be sure to confirm the specifications as well.

These do not come with a cover embedded to the base, so you'll need to purchase either the 39-375 or 39-451 as well. They are compatible with both operator styles. 

The other hardware and accessories can be found below the product description for the operators, on the website.