MiPow offers a pair of battery cases for the iPhone 4 and 4S--the $79 Maca Air and the $79 Maca 2200 Color Power Case. The two cases are very similar: Each sports a transparent top cover and edging--in fact, the top plastic caps are interchangeable between the two models. Each case ships with two such caps, so you have a backup in case you lose one. The back of each case is anodized metal that reflects trippy patterns in light, and multiple colors are available.
The Maca Air packs in 1200 mili-amp hours of power, compared to the (surprise!) 2200 in the Maca 2200. Another difference between the two is the amount of bulk: The Maca Air is impressively thin; The Maca 2200's added battery power requires that the case be thicker, and indeed it is. These differences in size and battery life explain the identical price point between these two models.
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To assemble these cases, just slide your iPhone into the main portion of either case, via the dock connector port. Then, slide the cap onto the top and push; It locks in securely. Rather than overlay the iPhone's buttons, both cases use cutouts to leave the volume buttons, Ring/Silent switch, and Sleep/Wake button accessible. That last button ends up a bit more deeply recessed than I'd prefer, but it's still quite usable.
Because the case uses the dock connector port to power your iPhone, both cases have Micro-USB ports on the bottom left edge. You use those ports to charge the case's battery, and you can also use it to sync your iPhone to your computer, if you don't rely on Wi-Fi syncing.
On the bottom right corner of the back of each case is a big round power button. You press and hold that button for a few seconds to turn the battery on or off. Next to the button on the case's back left sit four LEDs that blink when the case is charging or about to run out of power. These LEDs also indicate how much juice is left.
The metal back on each case is pretty shiny and looks cool. Unfortunately for me, however, the ridged texture gives me goosebumps: I really don't like the way it feels in my hand. I'm willing to stipulate that this is a flaw in my body and not the cases, and my wife confirmed that she didn't find its surface uncomfortable to touch.
Neither case extends past the iPhone's screen, so while they afford some protection for side and rear impacts, the cases do nothing to protect your iPhone's most vulnerable spot.
The Maca 2200--that's the more powerful one--measures 5 inches tall by 2.4 inches wide, and 0.61 inches thick. The Maca Air has the same height and width, but measures just 0.52 inches thick. Each is impressively slim for a battery case. The Maca 2200 weighs 0.25 pounds; the Maca Air weighs 0.23 pounds. If thickness is your top concern, go with the Maca Air, but I always err on the side of more power.
Macworld's buying advice
My favorite battery case remains the Mophie Juice Pack Plus ( Macworld rated 4.5 out of 5 mice ). It's much bulkier than either Maca case, but that bulk adds some protection. I prefer button overlays to cutouts, and the Juice Pack Plus leverages those over the Maca cases, too.
That said, if you value slimness and lightness, the Maca cases may be a better fit for you. The Juice Pack Plus is taller, wider, thicker, and nearly twice as heavy as either Maca case. If the Maca cases' feature sets match your needs, both the Maca Air and the Maca 2200 are fine options.
This story, "Review: Maca 2200 and Maca Air battery cases for iPhone 4 and 4S" was originally published by Macworld.