Window Vent For a Picture Window

I'm looking for a replace window vent, this part is in both the lower right and left of the picture window. I've attached a photo of the part and pictures of location on the window, as well as the window itself. I don't know the make of window, purchased at the time my home was built in 1998, unfortunately the store that my builder purchased the window from has since gone out of business. It was similar to say home depot, for builders.

The description of the window from the construction specifications states Double hung vinyl tilt in insulated with screens and grilles, however, this window is the picture window between the double hung windows and doesn't open. these vents are located on the outside at the bottom of the window. Please advise.

Thank you for your prompt attention to this matter.

Bridget