Why thousands of women in Iceland walked off the job at 2:38 p.m.

For thousands of women in Iceland on Monday, fighting for equal rights meant ditching out on work early.

Women across the country powered down their smartphones, closed their laptops, and canceled meetings at 2:38 p.m. to protest the gender pay gap, according to an Iceland Review report.

Why 2:38? The protestors didn’t just choose a random time.

Women in Iceland make roughly 18% less than their male counterparts, according to the latest European Union data. Which is good, compared to a lot of other countries — including the United States (which ranks 28th on the World Economic Forum’s Gender Gap Report; Iceland is first). But still pretty unfair.

Unless, of course, their work day was 18% shorter. Which means they’d get out at 2:38 p.m.

This isn’t the first time women in Iceland have gone on strike.

In 1975, labor unions and women’s rights organizations in the country organized the first Women’s Day Off. According to a BBC report, 90% of women in the country participated, including domestic workers and stay-at-home mothers. The strike paralyzed the country, forcing many men to take their children into the office.

“Probably most people underestimated this day’s impact at that time — later both men and women began to realise that it was a watershed,” Styrmir Gunnarsson, a former newspaper editor, told the BBC.

Iceland’s (and Europe’s) first female president, Vigdis Finnbogadottir, who joined that first protest 40 years ago, believes the mass demonstration helped pave the way for her election five years later.

This 2016 protest is the fourth time Iceland’s women have gone on strike — and the time of the walkout has gotten progressively later with each one as women’s relative wages have increased.

In 2005, protestors walked off the job at 2:08 p.m. In 2008, they left at 2:25.

But 2:38 p.m. is still not late enough!

At that rate, the wage gap in Iceland will take more than 50 years to close on its own. A WEF report estimates that the global wage gap may take as long as 118 years to sew up. But if the first protest changed the way the country values women’s labor, then perhaps the pressure from more massive events can speed up the clock.

Perhaps on a Women’s Day Off not too long in the future, they’ll be skipping out at the end of the day with their male colleagues.

Hopefully happy hour will still be running.