It's an idea that's taking off online and, now, in stores.
Bob Schwelm, the owner of Bryn Mawr Running Company on Lancaster Avenue, received his rush shipment of red socks in Monday afternoon.
All his proceeds will go to the victims' of the bombings.
"I have a feeling we didn't order enough. We've had calls off the hook," Schwelm said.
Schwelm and his wife were near the finish line of the Boston Marathon exactly one week ago to cheer on friends. They left the city to avoid traffic about an hour before the bombs went off.
Schwelm spent the next hour and a half trying to reach the friends he'd left behind in Boston.
"That was probably the hardest hour and a half I have ever experienced and, obviouslym, still very near and dear to think that we could have been there," Schwelm said.
He wanted to do something to help the victims and heard about the growing online effort to get participants in Philadelphia's Broad Street Run to wear red socks in support of the victims. He put in the order for red socks and the rush order came today.
"People are finicky about the socks they wear. We took that into account, with price also, so we have different levels of socks, three different price points, three different qualities," Schwelm said.
Schwelm watched coverage of the moment of silence in Boston this afternoon.
He hopes come May 5th, he'll be watching the Broad Street run and thousands of runners in red socks.
Meantime, he'll do his part to keep the socks in stock.
"We overnighted these. We'll do it again and continue to do it all the way up to the race," Schwelm said.