"Mittens don't clap," is how California-based cowbell importer Elisabeth Halvorson explains it.

And if you are the proud owner of a cowbell in North America, chances are it passed through her hands en-route to the U.S.

"Bells have been used, especially in downhill skiing, for a long time. It started in Switzerland, where in summer the cows all walk around the mountains with bells on," added Halvorson.

"But in winter they are in barns, and the bells are hung up. All the farmers were also the ski racers in the old days, so their families went in the barns and grabbed the bells.

"Olympians have told me that when they're at the bottom of the hill, they can hear a little shouting but they can really hear the cowbells."

Winter Olympic icon

Watch any ski race on television and you will hear the same dull, persistent background clanging.

Turn up in person and dull is the wrong word: stand in the right (wrong?) place and it's more a cacophony.

Already steeped in Alpine history, cowbells have become a global success and Winter Olympic icon over the last two decades.

Halvorson got into the business ahead of the Salt Lake City Winter Games of 2002, where the golden, oblong bells became a sought-after souvenir.

"It's really a European cultural thing that, in the past 15 years or so, has grown here in the States," she told CNN.

"If the Swiss are coming to an event they'll bring really big bells, a foot high or more. Belarus has some good bells too, and they come with sheepskins on.

"How many do we sell? I quit counting when we reached 70 tons -- and that was before the 2002 Games."

Halvorson imports bells manufactured in Norway by a small family business Moen Bjøllefabrikk, based in a factory south-west of Oslo.

"My grandfather started it in 1922," says head of the company Lena Alette Moen Grude. "He began producing bells for his neighbors' domestic animals and sheep."

The company has changed with the times -- it now makes GPS tracking devices for livestock -- but when a Winter Olympics is within sight, cowbells become their hottest commodity by far.

"We produce approximately 30,000 bells each year," says Moen Grude. "For us, it started before the Winter Olympics in Lillehammer in 1994. The fans saw it as the only souvenir that let them take the spirit of the Olympics back home.

"For the Salt Lake City Olympics, we produced 68,000 bells -- more than two years' production -- in two months. When there is a Winter Olympics, it dominates our company.

"I remember producing the bells for Salt Lake City, working late at night and listening to the Games on the radio. I could hear the bells being rung in America as I was engraving them in Norway. That was special."

Changing fabric