Hewlett-Packard unveiled a Windows-powered touchscreen tablet computer on Friday aimed at professionals, the latest entry into a growing market dominated by Apple's iPad.

The "HP Slate 500," which features an 8.9-inch (22.6-centimeter) screen, slightly smaller than the iPad's 9.7-inch (24.6-cm) display, costs 800 dollars, about the same price as the top-of-the-line iPad.

While the iPad is aimed more at consumers, HP is targeting its device at business customers and touting its ability to handle documents, spreadsheets and applications from Microsoft.

HP described the Slate 500 as the "ideal PC for professionals who don't usually work at a traditional desk, yet need to stay productive in a secure, familiar Windows environment."

"The ability to easily incorporate custom business applications differentiates this product and ultimately enhances the user experience and saves time for HP's business and enterprise customers," it said in a statement.

The Slate 500 weighs 1.5 pounds (0.68 kilos), the same as the iPad, and runs Windows 7, the latest version of Microsoft's computer operating system.

It has two cameras -- one still and one video -- and a USB port that allows a user to connect a keyboard, mouse or printer.

The Slate 500 offers Wi-Fi connectivity to the Internet but does not have 3G cellular access. It will be available only in the United States for the time being.

The device has five hours of battery life and comes with a digital stylus that lets users write notes directly on the screen.

HP unveiled the Slate 500 just two days after South Korea's Samsung announced it would begin selling its answer to the iPad, the Samsung Galaxy Tab, in the United States on November 11 for 600 dollars.

The Galaxy Tab, which is powered by Google's Android software, features a seven-inch (18-centimeter) touchscreen.

Apple chief executive Steve Jobs slammed seven-inch tablets on Monday saying the screen was too small and the devices would be "dead on arrival."

According to market research firm Gartner, sales of tablet computers are expected to soar from nearly 20 million units this year to 55 million next year.

Apple sold 4.2 million iPads last quarter.