The Trump administration made waves this month when it raised tariffs on $200 billion worth of Chinese-made goods, effecting various American retailers.
The typical "performance" running shoes may go from current $150 to $206.25 and hunting boots from $190 to $248.56.
While US tariffs on all consumer goods average just 1.9 percent, they average 11.3 percent for footwear and reach rates as high as 67.5 percent.
And while $7 billion certainly sounds like a large figure, how does it break down?
The firms said the industry already pays $3 billion in duties and that additional tariffs would increase costs and prices.
In the escalating trade war with Beijing, Trump this month increased existing tariffs on $200 billion in Chinese imports to 25 per cent and is threatening to extend those duties to almost all Chinese products imported into the United States. President Trump has threatened to implement duties on an additional $300 billion in Chinese goods if an agreement can not be reached.
The U.S. Trade Representative is now evaluating that additional 25% increase, which includes footwear.
In an interview with Fox News Channel recorded last week and aired on Sunday night, Trump said the United States and China "had a very strong deal, we had a good deal, and they changed it".
Some companies have spent the past several decades setting up their supply system in China as factories there perfected low-priced production with simple shipping routes to the U.S. West Coast. Footwear and clothing retailers, in particular, mostly still require humans to put together goods.
Footwear companies that signed the letter to President Trump have different levels of dependence on China. Nike made about a quarter of its footwear and apparel in China during its 2018 fiscal year. China has retaliated by increasing tariffs on United States goods.
Finding substitute capacity for factories in other countries while keeping costs low could can take years or even decades, retailers say.
However, the shoe-makers and retailers say that while they have been moving their sourcing away from China: "Footwear is a very capital-intensive industry, with years of planning required to make sourcing decisions, and companies can not simply move factories to adjust to these changes".