PUBLISHED: 12:00 EST, 6 October 2012 | UPDATED: 12:04 EST, 6 October 2012

This new hacker invention may look like a harmless dry erase marker, but in truth it’s the ultimate electronic lock pick.

In a post titled ‘James Bond’s Dry Erase Marker,’ hotel hacker Matthew Jakubowski demonstrates how anyone can build this pocket-sized device which will open the lock on an estimated 4 million hotel rooms.

‘I guess we wanted to show that this sort of attack can happen with a very small concealable device,’ says Matthew Jakubowski, a security researcher with Trustwave, told Forbes. ‘Someone using this could be searched and even then it wouldn’t be obvious that this isn’t just a pen.’

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