CES 2011 Research in Motion is to launch a 4G version of its much-anticipated tablet, the PlayBook, this summer with US mobile operator Sprint Nextel.

For the first time on Wednesday, RIM provided a hands-on demonstration of the Playbook, a 7in touch-screen tablet. A Wi-Fi only version launches in the US in March, and RIM is reporting huge interest in its corporate heartland.

The choice for RIM to go with Sprint has raised eyebrows, as Sprint uses a high-speed wireless technology incompatible with networks being built by the bigger mobile operators. Also Sprint is the weakest of all the big US operators.

However, Jeff McDowell, a senior veep at RIM, said at a CES briefing that the company chose Sprint was because it has the most "ubiquitous 4G network at this point".

The Playbook weighs around 400g, measures less than 10mm thick and has multi-tasking software with the ever-popular rotating carousel browsing feature. McDowell tried to clear doubts about its battery life by saying it would last as long or longer than other 7in tablets, although he gave no details.

The war is on between tablet manufacturers and McDowell brushed aside Apple's claims that Flash is a battery hogging technology as "absurd generalisations".

Apple CEO Steve Jobs famously said that 7in tablets will be "dead on arrival" when they hit the market. RIM clearly disagrees, but it is looking at more sizes for the Playbook, according to McDowell, who declined to comment further.

Although non-specific on pricing, he insisted the Playbook would retail at less than $500 (£311).

It's likely that Europe will see delays on availability. ®