It seems that the Nexus 7 Android-powered tablet has a hidden feature that neither Google nor Asus -- the manufacturer of the tablet -- have revealed.
A video has been uploaded to the internet that shows that Google's new tablet has a sensor located bottom left-hand side of the device -- when held in portrait orientation -- that can put the device into sleep mode when a magnet is bought near.
This is similar to the feature that Apple has built into the iPad 2 and iPad 3 to control the "Smart Cover" used to power down the device when the cover is closed, and it seems that the Microsoft's Surface tablet will also have a similar feature.
It is unclear why the Nexus 7 has the feature built into the tablet yet it has not been advertised anywhere.
Google does sell a cover for the Nexus 7 called "smart cover" which is described as a "tough, yet snug-fitting polymer case with a non-slip matte texture that protects Nexus 7 from bumps and scratches, and also provides additional grip," but no mention is made that it has the ability to put the device to sleep like Apple's own cover.