Need help, broken driver window piece 69 Dart

B3422w5 said
Window fell down racing the other night, propped it up. Found out the piece I will show in the picture is broke.
1. What do you call it.
2. Where would I get one

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It’s one part of a two part piece that holds the main door window to the bottom bracket. The blue bit at the bottom of the window in the pic. They are available as part of a set or B3422 is right, you can get just individually.