There are a couple differences from the initial model released in 2013. The Glass folds up like a normal pair of glasses, which should make storage a little simpler, and it could make the headset a little more forgiving in the event of an accident.
The pictures on the FCC site make it look like the Glass isn't attached to a frame, so it should be possible to pair the device with any set of glasses. It also looks like the charging port will be magnetic, similar to Apple's MagSafe adapter. A preliminary user manual was also included in the FCC filing.
This latest version is likely to be aimed at businesses, which makes sense considering the public's lukewarm reception of the original Glass. The business-oriented Glass, referred to as the "Enterprise Edition," will reportedly ship with an Intel Atom processor, which you'd have to imagine would work much better than the Texas Instruments chip used in the last release—TI shut down its smartphone division and canceled support for those products shortly after Glass launched.