Toshiba plans to launch this month a line of notebook PCs that weigh as little as 1.9 pounds, are 0.77 of an inch thick, and sport up to 12.5 hours of battery life.

The Japanese computer maker plans to release the slim, light notebook June 22 in Japan, and in the United States and other countries soon afterwards. The new product will be sold as the Dynabook SS RX Series in Japan, and the Portege R500 Series in overseas markets.

Models that ship with a 64-Gbyte flash drive weigh less than two pounds, while systems with a 120-Gbyte hard drive weigh 2.4 pounds. Other than the weight, the models have the same form factor, and both boast up to 12.5 hours of battery life.

The series includes a 12-inch LED screen with a backlight that can be turned off and on for better viewing outdoors and indoors, respectively. The machines, which are powered by an Intel Coreaa 2 Duo processor with a clock speed of 1.06 GHz, also have a rewritable DVD disk drive that's 0.28 of an inch thick.

The notebooks can withstand a fall of as much as 29.5 inches, and are resistant to accidental spills, which means the user has time to save data and shut off the machine after spilling water, coffee, or soda, Toshiba said.

While Toshiba calls them notebooks, at least one market researcher places the new product in the category of ultramobile PCs, which are smaller than laptops but larger than smartphones, and are good alternatives on short business trips to heavier notebooks. William A. Peters Jr., analyst for Technology Business Research (TBR), said in e-mailed comments that Toshiba's new line is similar to recently previewed or introduced products from Palm, Samsung, Sony, Nokia, HTC, and Fujitsu.

Toshiba's offering has an early advantage over many of the other products by running Windows, which means users can run Microsoft Office, Peters said. Palm, for example, uses Linux in its Foleo device, which means compatibility issues are likely to arise in trying to view Office files.

Rivals, however, are expected to catch up soon with second- and third-generation products. "TBR believes the deciding factor will be cost," Peters said. "With the Portege R500's low end costing $1,999, TBR expects Toshiba to increase offerings, or significantly lower price to compete with its much less costly rivals in the UMPC market." Foleo, for example, sells for $599.

Ultramobile PCs are expected to become the next big thing in the computer industry over the next couple of years. Intel, for example, is gearing up with processors suited for a variety of devices that offer a limited number of features in exchange for easy portability.