This new bunch all began with a paper leak way back in late June, remembering the new naming scheme with codenames Fate, Cindy, Zeta, and Helen. All of this now ends as Nokia has formally unveiled three new phones that would be having the new Symbian Belle operating system. The official page mentions of the loudest, brightest, and the smallest smartphones Nokia has to offer.
The 600, being the loudest, has a unique feature that goes around music. From the speakers, FM Radio, and the MP3 player, down to the long battery life for accommodating constant media play, the 600 is perfect for the audiophile. The 700 is known to be the smallest but has the biggest features. First of all, the body and screen are scratchproof; the browser has fast connection speeds, and it also has NFC just like 600. The brightest 701 relies on the quality of its visuals to provide a richer mobile experience.
Source: Nokia Symbian Belle Page