Netbook pioneer Asus has unveiled four new tablet devices, including the 10.1in touchscreen Eee Pad Slider with the latest version of Google's Android mobile OS,  'Honeycomb', and the 12in touchscreen Eee Slate E121, which has Microsoft's Windows 7 OS.

The company is among the first to unveil its new iPad rivals ahead of the International Consumer Electronics Show in Las Vegas. The show officially opens on Thursday, with as many as 100 new tablets on display.

The Eee Pad Slider is special for a few reasons. First and foremost is the software, Honeycomb, which was expected to be unveiled officially at a Motorola press conference taking place today.However, Asus got a jump on the competition. The tablet sports a 10.1in touchscreen with a keypad that slides out, similar to mobile phones with sliding keyboards, for laptop-like typing.

Asus Eee Pad Slider

The device also boasts an nVidia Tegra dual-core processor for strong graphics performance and has dual cameras on board.

The Eee Pad Slider will launch in May and will be priced between $499 and $799 (£320 and £512) depending on several factors, including content and wireless contracts. UK pricing has not yet be revealed.

The Asus Eee Slate E121 has an Intel Core i5 processor and Microsoft's Windows 7 OS, for a full PC experience. It is focused on HD multimedia, with an HDMI port in addition to its USB port.

Asus Eee Slate E121

"It's the most powerful tablet in the world... It's a PC, but it's not very PC," said Jonney Shih, chairman of Asus.

The device will launch in January for between $999 and $1,099 (£641 and £705), the company said. Once again, Asus did not reveal UK pricing.

The company's smaller tablet, the Eee Pad MeMO, has a 7in multitouch screen and uses Qualcomm Snapdragon chips and Google Android. It has dual cameras and can handle 1080p high-definition playback. A media phone extender, the meMIC, gives it phone calling capabilities. The device will launch in June for between $499 and $699 (£320 and £448).

Finally, the Asus Eee Pad Transformer is a 10.1in touchscreen tablet that also has Google's Android OS on board and nVidia Tegra 2 dual-core processors inside. The device is named after its ability to transform into a laptop from a tablet. The screen comes off the full-sized keyboard. The screen part is thinner than an iPad, at 12.98mm, and the device offers Flash video and full HD multimedia. It will launch in April for $399 to $699 (£256 and £448), the company said.

Apple presided over the tablet craze by launching the iPad in April and shipping nearly eight million units through the end of September. By being first, Apple has set the tone for the entire market. The company's App Store, e-books, music and other content have made it important for tablet makers to use the same OS in their tablets as in smartphones so everything can be shared. Asus has diverged from the pack by putting Windows 7 on the Eee Slate E121, which is also one of the biggest tablets so far, at 12in.

See also: Microsoft targets Acer and Asustek over Android

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