Safety pins are flying off the shelves of craft stores around the Twin Cities as citizens use them to show solidarity with people who fear President-Elect Donald Trump’s rhetoric and agenda.

A movement encouraging Americans to fasten a safety pin to their shirt identifying themselves as an ally with groups who feel marginalized by Trump — including minorities, women and the LGBTQ community — has become popular on social media. Thousands have taken selfies while wearing the single safety pin, which is meant to act as a symbol of inclusion.

On Saturday, local hardware stores and several craft giants like Michaels began selling out of safety pin packs. Managers at Michaels locations in Minneapolis, Roseville and Richfield said Saturday that they’ve noticed an uptick in customers shopping specifically for safety pins since Tuesday’s presidential election.

Photos posted on Twitter on Saturday showed empty shelves at multiple locations, which workers said have not been restocked since Halloween.

“It’s been pretty heavy today,” said Richfield manager Kevin Kurhajetz, who hadn’t heard about the phenomenon until the sales rush began. He filed a request for a new order of safety pins with the district manager. “We’re usually pretty good about getting on trends like that,” he said.

As anti-Trump protests continue in more than a dozen cities throughout the United States, participants are using the simple and cheap (a pack of 200 safety pins runs under $4 at Target) method to show support for people who are fearful for their safety. The pin movement also asks the wearer to intervene if they witness harassment.

Anthony Ceballos, of Minneapolis, said he takes that pledge very seriously. The small, unspoken gesture provides an extra level of security during a time when people feel particularly vulnerable, he said.

“I felt that [it was] part of my duty, especially as a person of color who identifies as gay,” said 26-year-old Ceballos, who began wearing colorful safety pins on his jacket Friday. “In this climate we absolutely need to know that we’re there for each other.”

In Minnesota, back-to-back demonstrations have drawn thousands into the streets, condemning the racism and sexism they say Trump represents. At least two metro-area schools have been vandalized with racially charged graffiti this week, penning anti-immigrant messages that made students feel uneasy.

Trump supporters and others also have taken to social media to criticize the protesters and social media outcry, saying that Americans should accept the election results and move on.

This isn’t the first time people have worn safety pins to support a political cause. British activists created the #safety pin movement in June following the Brexit vote as a way to show refugees and immigrants they had friends. Americans, faced with a severely divided election, appeared to be inspired by that action.