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A Colorado sports apparel store is closing after its owner's decision to boycott Nike gear as a protest against the brand's embrace of Colin Kaepernick proved to be a financial death blow.

Stephen Martin, owner of Prime Time Sports in Colorado Springs, took all Nike goods off his shelves this past fall after the global brand launched a marketing campaign with the former San Francisco 49ers quarterback — "Believe in something, even if it means sacrificing everything."

Martin admitted that taking the products off the shelves hurt his business.

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"Being a sports store and not having Nike jerseys is kind of like being a gas station without gas. They have a virtual monopoly on jerseys," he told NBC News on Thursday.

Martin decided Sunday that his business couldn't go on and started marking down goods 40 percent off. He estimated that it'll take four weeks to liquidate all his inventory.

Believe in something, even if it means sacrificing everything. #JustDoIt pic.twitter.com/SRWkMIDdaO — Colin Kaepernick (@Kaepernick7) September 3, 2018

“For 21 years, this was my baby. I built this from a kiosk. Now, I feel like I'm leaving under a cloud of darkness," he said. "But I feel good inside, that I didn't put profit over principle. That’s what makes it easier to live with."

Back in the 2016 NFL season, Kaepernick took a knee during the national anthem protesting racism against African-Americans. Other players joined Kaepernick, leading to a backlash from critics who believed they were disrespecting America.

Kaepernick opted out of his contract with the 49ers following the 2016 campaign and no team has signed him since, leading to a lawsuit against the NFL accusing its owners of collusion.

Martin, 64, said his business was already headed for the sidelines due to the internet.

"That's a big part of it," he said, referring to the Nike boycott's effect on the store closure, "but it's not all of it."

"As a brick-and-mortar, we're facing pressure from online sales."

Despite Martin's boycott of Nike apparel, Prime Time Sports showed a $13,000 spike in sales in November and December, compared to those same two months in 2017.

"That really amazed me," Martin said, "until I realized that seven of my competitors within 30 miles had closed and that was driving my sales. I was just the last one standing."