MeMawMaw,
I have little information on Unique. It was a popular brand name for Davis. Based on the serial number I received earlier I believe it to be a Davis model H made sometime around 1905. A photo would be good to double check. Davis used 2 different shuttles and bobbins for their Underfeed models (Unique). The one is full sized and the other is 3/4 sized. Unique is full sized so the shuttle and bobbin are larger. The full and 3/4 sized bobbins and shuttles will not interchange.
Jon