The Chinese-made inputs Apple asked to have exempted from the 25% import tax include parts like a power supply unit, stainless-steel structural enclosure, circuit boards and completed mice and trackpads, according to the filings.
"There are no other sources for this proprietary, Apple-designed component," according to the filings. Apple also said that there are no comparable products for the 15 parts from United States-based or other international sources.
The filings underscore the tightrope Apple is walking due to the U.S. trade war with China. Although Apple's products are designed in California, and contain parts and technology from the U.S., final assembly for most of Apple's products is completed in China. Apple assembles some Mac computers in Cork, Ireland.
While the filings do not specify which Apple product houses the components, descriptions of the parts indicate they are inputs for the Mac Pro, a high-end computer set to go on sale later this year starting at $5,999.
Earlier models of the Mac Pro were assembled in the U.S., but the Wall Street Journal previously reported that a new redesign announced earlier this year will be manufactured in China. Apple declined to comment.
Apple opposes the U.S. tariffs, which went into effect last fall and were raised to 25% in May. Apple CEO Tim Cook has said he personally told President Donald Trump that tariffs are the wrong approach to China. Although Apple warned last fall that the tariffs would affect "a wide range of Apple products," it ended up dodging the duties for products including the Apple Watch and AirPods.
Bloomberg first reported the filings.