Aluminum Glazing Bead for Weathershield Casement window.
Limited to existing inventory then completely discontinued.
Used in conjunction with a vinyl interlocking strip.
To remove, the vinyl strip was pushed over to release the aluminum bead. If you force the removal you will break the vinyl strip, which is not available and you will not be able to re-install the Aluminum bead.
Circa: Late 1980's - 1990's