By now, it's a common story: A trendy product from a hot startup starts to break into mainstream popularity, and suddenly Amazon has a copycat version.

The e-commerce giant's latest target is Allbirds, the 3-year-old maker of "the world's most comfortable shoe," with a burgeoning reputation for quality and commitment to environmental sustainability. The Amazon-branded 206 Collective Men's Galen Wool Blend Sneakers bear a striking resemblance to Allbirds's most well-known product, the Wool Runners--at a significantly lower price point. The Allbirds shoes sell for $95 per pair, compared to Amazon's $35-45 price range.

Amazon appears to have been selling its wool shoes since at least June 19, the date of the product's first online review. "They are remarkably similar in concept to wool runners by a currently trendy, environmentally friendly shoe company," that review reads.

In an emailed statement to Inc., Allbirds responded:

We're aware of the shoes released by Amazon's 206 Private Label and its similarities with our Allbirds Wool Runners. While we have no specific response at this time, we wholeheartedly echo the sentiment in the top review for Amazon's product: "I hope Amazon has made these shoes with the same environmental ethos that Allbirds have. It's not enough to simply copy their shoes, they need to follow their environmental actions too!"

That statement comes on the first day of the Global Climate Strike, a week-long event featuring planned corporate and school walkouts on Friday to protest international climate change policies. More than 1,600 Amazon employees are expected to participate, according to a Medium post published on September 9 by a group called Amazon Employees for Climate Justice. Meanwhile, Allbirds is closing its U.S. and U.K. stores and offices until 1 p.m. Pacific Time on Friday to allow its employees to join.