The new models are part of a family of cellphones that Motorola is building around the Razr, which has helped the company revitalize its brand in the last two years.
As competitors like Samsung followed suit with their own skinny phones, Motorola hopes to keep up the momentum of the Razr with new models inspired by its style and four-letter name. Motorola has sold about 50 million Razr phones since they were first launched in late 2004.
Its latest phones included phones designed for high-speed mobile Web-surfing and phones with dedicated buttons for cameras and music players as well as a new sliding format.
The Krzr, a 42-millimeter-wide phone, flips open like the 54-millimeter-wide Razr but is slightly thicker as it has a camera and space for extra storage for up to 500 songs.
"We think this is big," said Chief Executive Ed Zander, at the phone launch event in a Chicago suburb. He said Motorola aims to eventually sell 500 million versions of the Razr.
The Krzr, made of magnesium, polished chrome and hardened glass, has a reflective surface and will come in two colors: gray and blue.
China Mobile, the world's top cellular carrier by subscribers, has already agreed to sell the phone, which Motorola says will be sold worldwide by the end of this year.
The narrower Krzr phone should help the company attract new customers, including women, said Tracey Koziol, an executive in Motorola's handset division.
"For people with smaller hands, it does probably fit better than the Razr, especially for Asian customers and ladies," said Koziol, adding that most cellphone carriers around the world have shown interest in the product.
The Krzr would probably sell at around the bottom of the high-end price range, Koziol said but declined to give a specific figure. Analysts describe phones that sell for more than $250 as high-end, and $125-to-$250 phones as mid-tier.
Ron Garriques the head of Motorola's device business said it expects the latest products to ship at a rate similar to the Razr in their first quarter on the market. The Razr sold 750,000 phones in its first three months on the market.
Charter Equity Research analyst Ed Snyder was impressed with Motorola's new line up and its fashion focus but said the target was "a little optimistic."
Others were not ready to predict as a lot of factors would come into play.
"The key is going to be the extent to which they're able ramp up production in volume and what the quality levels are," said John Bucher, an analyst for BMO Capital Markets.
The new phones could be particularly important in the U.S. market in the fourth quarter this year, another analyst said.
"I think they're key to the fourth quarter and designed for people who bought the Razr two years ago," said Oppenheimer analyst Lawrence Harris as the first Razr buyers would be coming toward the end of their two-year contracts by then.
Motorola also unveiled the Rizr, which is 46 millimeters wide and slides open. It gives users the option of turning the phone sideways when it is closed to take landscape photographs using a dedicated button for its 2-megapixel camera.
Available in blue, red and black, the Rizr will initially be sold just to operators using GSM networks. It is expected to sell in the mid-tier price range.
Motorola also unveiled three phones for high-speed wireless services. The Razr XX and the Razr Maxx will work on networks based on HSDPA, a faster version of GSM, and will allow users to stream video or music to the phones over the air.
The Razr XX is expected to price in the mid-tier range while the Maxx, which has room for extra storage and a 2-megapixel camera, is expected to sell in the high-end range.
Motorola also debuted the SLVR L7c, a candybar phone that will run on EV-DO, a faster version of CDMA.