Burger King launched a cause marketing campaign to end the “pink tax,” the practice of charging more for a similar product simply because it’s marketed to women.

In a video posted on YouTube, female customers were asked to pay more for chicken fries because they were packaged in a custom pink box. When the women refused, the manager asked if they speak up while experiencing the same price disparity in a drug store. The answer was no.

“We created this experiment with fan-favorite Chicken Fries to demonstrate the effect of pink tax and how everyone should pay the same for the same products—whether it’s pink or not,” Christopher Finazzo, North American president for Burger King said in a press release.

To spread awareness of the campaign, Burger King is offering its Chicken Fries at a lower price of $1.69 in select US restaurants. The pink chick fries box was available on Thursday for a one-day promotion in select locations in Miami, New York City, Los Angeles, San Francisco and Chicago—and cost the same as regular Chicken Fries.

Burger King’s “Chick Fries” campaign encourages viewers to support H.R. 5464, the Pink Tax Repeal Act introduced by Congresswoman Jackie Speier in April. If passed, the act would allow the Federal Trade Commission to enforce violations. In addition, charging more for similar or identical products based on gender may result in civil action by the State Attorneys General.

According to a 2015 study by the New York City Department of Consumer Affairs, the female version of many products cost more 42 percent of the time.

The quick service restaurant has advocated for equality in previous campaigns, such as its famous Proud Whopper—a Whopper hamburger with no changes except for a rainbow-colored wrapper that said, “We are all the same inside.”