Vinyl Glazing Bead

Snap in kind. 
1 1/2 inch wide
The little projection that snaps down into the track is about 1/4" (seems just slightly over that but close).
I had thought these windows were Pella as some in our home were marked Pella and some were not. I thought the design and serial codes were similar to the ones marked but they were custom windows and Pella refused to help me may saying that they had no record of the sale/home location so we aren't sure their origin. They were made in 2006 or 2007.