BARCELONA, MOBILE WORLD CONGRESS – Pssst… don’t tell anyone, but I just saw Mophie’s new Juicepack Air for the iPhone 5. After months of abusive complaints in forum and comment threads the world over, the Air is now finally… almost… available for the slim new iPhone.

Short form: it’s bigger than the Helium, yet slicker than the old Air for that fat monster the iPhone 4. It also has a pass-through mute button, which engages with a very satisfying click.

Otherwise, it’s a utilitarian battery case from Mophie, the OG of battery packs for the iPhone. It’s fairly thick, but has cutouts for the headphone jack (bottom edge), camera and flash and neat little channels which reflect the sound from the speakers forwards through a pair of grilles.

Inside is a Lightning connector plus a 1,700mAh battery which will give a full charge to an iPhone 5 (the thinner Helium manages slightly less).

It goes on pre-sale Monday 25th (tomorrow as of this writing) and will cost $99.