Mattel's Dallas (19??, LED, 9 Volt, Model# ??)
U. S. Patent # 4,410,181
Invented by: Douglas Lapp and Luan Tran (according to the patent)
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This is actually a complete board game based on the old 'Dallas' TV show. It includes a handheld electronic device to assist in game play. This is sometimes found by itself, and is thought to be a stand-alone handheld game.
Do I have this? Yes, boxed (complete).