Image: Apple If Apple’s super-thin iPhone Air has one drawback, it’s the battery life. Apple understands this, which is why it makes a MagSafe battery pack that fits perfectly under the iPhone Air’s camera bump. Normally $99, it’s on sale for 20 percent off at Amazon right now, the first time we’ve ever seen it this low. Like the phone itself, the iPhone Air MagSafe Battery ​​​​​​​ is super slim and stylish, and won’t add too much bulk to the back of the phone. It’s d...