There seems no section on applevis for external batteries and the item is both, though the prime purpose is as a battery; the case is only to make both the Iphone and battery one compact unit. Warning: this message is longer than an east-bound grain train at harvest! The power pack I will be discussing for the IPhone 4S is also available for the IPhone 5. The model is I believe rather steeply priced at present at $71 Canadian. The unit I purchased is: seidio bd4-pbyiph4-gr innocell Decent information on the model I purchased can be found at: http://www.amazon.ca/Seidio-BD4-PBYIPH4-GR-Innocell-Packaging-required/dp/B00BFO3OG2/ref=sr_1_1?s=electronics&ie=UTF8&qid=1366244222&sr=1-1&keywords=seidio+bd4-pbyiph4-gr+innocell rather than at the manufacturer's site. The link is a mile long so it may have to be copied/pasted in pieces. Technical Details (from the Amazon page) ? First iPhone 4/4S power case with a removable battery that is certified by Apple ? Sleek case (~0.73 cm) with our signature soft-touch coating provides scratch protection without adding much bulk ? Case includes a 1750mAh battery and slot allows users to swap out battery with a spare ? Included micro-USB cable allows you to sync and charge your iPhone 4/4S without the hassle of removing your case ? For use with Apple iPhone 4/4S - Dimensions Size (LWH): 4.95 inches, 2.43 inches, 0.65 inches so, your Iphone 4/4s gets thicker by about 1/4 inch, wider by about 1/8, and longer by about 3/4. Were I to rate this case on a scale of 1 to 10, I would score it a 7, only due to both seriously lacking and unclear included instructions, and the "glass onion" effect of the web site. Following any links or other search techniques using my speech program features did not turn up any thing informative on the web site--shame! Just in case, the manufacturer's web site is: www.seidio.com I offer the following instructions: Courtesy of Doug and John; even the technicly skilled eyesight of friend John found this apparently simple case/battery charger-enhancer's Dubious instructions confusing. The package contains four components plus the dubious instruction sheet. 1 The main unit is like a tray with the bottom end, which includes ports for speaker and microphone, being the same thickness as the iphone and about 1/4 inch extended beyond the phone. 2 The battery fits in the thin section of the tray and goes easily only one way, no forcing reqquired. 3. The "lockin in" section looks like a picture frame whose thinner botton edge snaps around the edge of the tray. The frame includes buttons for up/down volume, a matching on/off button, an opening for the now recessed mute/vibrate switch, and of course the ports for speaker and mike. The mike port also contains connections for the included and apparently proprietory supplied USB cable. Snapping the frame together requires considerable finger gymnastics and quite firm pressing. Removin g the fram is also a bit of a challengwe and the slot provided at the bottom end of the case is not the best method for pulling the two sections apart; rather, starting the removal from one side is the best strategy. It's actually not as hard to do as to describe. 4. The usb cable can be used to charge both the iphone and battery though, doing the math, one would require a total of 7 hours to charge both at the same time. I am presently charging both separately for a total of four hours. The Innocel (seidio case) and phone charged separately take about the usual 3 or 4 hours (I use 4 to be sure when I can.) Once everything is assembled and charged, the first battery to "kick in" is the cell phone. Once discharged, according to the instructions to below 50%, it is possible to engage the innocell battery. The so-called button for the purpose is not discernable by touch and in fact, even visually the on/off symbol took friend John several frustrating minutes to see; the simbol is tiny. To invoke the innocell, press down on the right side of the right-hand bottom corner of the seidio case on the phone face. The Iphone will give the same chirp as when one connects to the usual charging source and the battery indicatore will say "charging." Pressing this area again gives the IPhone power disconnect tone. I haven't exercised the Innocell yet but first charge braught my Iphone 4S up to about 80%. Oh yes, there are also some lights which light according to charge and/or functioning level. I really don't know nor care how they work, or don't work, since I can't see them anyway. So far, I get about 5 hours using Blindsquare GPS, my bus schedual ap, Bluetooth off, and screen turned off. Hope this proves useful to someone; it took longer to write than to read.
Seems like a good case, but I