Beijing is stingy about allowing foreign manufacturers to add new models to their product lines.

This machine added models of the tongue and lips, enabling it to produce consonants as well as vowels.

Women's magazines took note of Lizzi's popularity and have been slowly adding plus-size models to their fashion spreads.

It has since added less costly models, and its retail share has bounced back to 16 percent.

On Tuesday, Chrysler added new models to its program and increased some of the discounts to as much as $2,500.

G.M. has had little trouble adding models, including several aimed at Chinese families.

Many of the more aggressive dealers have responded by adding imported models.

In 1952, the company acquired Laplant-Choate, which added various models of scrapers to its construction equipment line.

But adding models to one line also adds complexity for line workers and makes high quality tougher to maintain.

Indeed, analysts say the company's restrained approach to adding new models and production capacity is in large part responsible for its current power.