Brian Kolfage, a Florida military veteran, recently convinced Americans to donate millions of dollars for a privately built wall on the U.S. southern border. Now he has jumped into a new venture: hawking millions of protective face masks that are in critically short supply during the coronavirus pandemic.

About a month ago, Kolfage formed a business called America First Medical, which offers on its website and in social media pitches to broker large-volume sales of high-grade masks known as N95s. He said he charges about $4 each — several times the prepandemic prices but a few dollars less than some hospitals, nursing homes and first responders are now paying.

Though he hasn’t yet found buyers, Kolfage says he’s found masks all over the world, including stockpiles hidden away in warehouses in Japan and Eastern Europe. If a deal goes through, he will collect a commission between 1 percent and 3 percent, depending on the size of the order, he said.