This is the rear playfield glass channel which mounts on the cabinet to support the back edge of the playfield glass.
The 23" 03-8091-2 channel molding is for all Williams/Bally wide body pinball machines made in the 1990's. It is pre-drilled and notched. The list of machines which use this part is:
• Twilight Zone
• Indiana Jones
• Popeye
• Road Show
• Judge Dredd
• Demolition Man
• Star Trek The Next Generation