New York—Manufacturer J.J. Marco has seen 15 years of success in supplying jewelry designs to retail jewelers across the United States, but since making its own plunge into retail, the company's growth has reached new heights.

In December, owners Mark Cohen and Julianne Jaffe opened a flagship store on Madison Avenue on the Upper East Side of Manhattan, a retail mecca for the city's stylish. The newbie retailers placed their classic, easy-to-wear designs in pretty window displays and then sat back to gauge reactions. Before long, shoppers were peering in.

"Our look is a fit in our new neighborhood," says Jaffe. "We are definitely in a self-purchase market here. When women pass our windows and see something they like, they come in and purchase it."

That immediate response factor created more than just buzz around the store location. It created something of a retail lab environment. The owners began using the storefront as a proving ground for new designs and collections, and a way to fine-tune their merchandise offerings, both for sale in New York at retail and for distribution to Marcos' retail accounts across the United States.

"We change our window every week," says Jaffe. "We can put new pieces in the window and we know right away if this is a collection that is going to take off, and is something we can grow."

Because Cohen designs the pieces and the product is manufactured in the United States rather than abroad, turnaround time for new lines is remarkably short, allowing a nimble response to consumer reaction.

Jaffe says the same technique of display-and-response also allows J.J. Marco to try out designs before showing them to their retailer accounts around the country.

"We will take a chance on something before we ask our retailers to take a chance on it," she says. "We will try new designs in our store for two months before we bring it to market, and we will know if it is good."

Retailers have responded well to the opening of the store, with some visiting to do their buying, where they mix and match to suit their own inventories. And, there's a third benefit to the new store: the visibility and cachet—read "brand recognition"— afforded by the upscale location.

"We are a billboard for our brand on Madison Avenue," says Jaffe. "Once you have a presence there, you have arrived."