Brunswick Corp. (plaintiff) manufactured and sold Mercury marine outboard engines. All of the Mercury engines were black in color, and some of Mercury’s advertisements highlighted this color as a feature. Mercury filed an application to register black as an outboard motor color as a trademark. British Seagull, Ltd. (defendant) was a competitor and, along with another competitor, opposed the registration, claiming that the color black for outboard motors served a competitive need because it coordinated easily with many boat colors and served to make the engines appear smaller. The Trademark Trial and Appeal Board denied Mercury’s application, holding that the color black for outboard engines was not eligible for trademark protection because it was a functional feature due to competitive need. Mercury appealed.