The iPad 2 (Wi-Fi Only) was proclaimed to be the start of a "post PC" era (although it still originally was required to be "tethered" to a Mac or Windows PC for synchronization and updates). Just like the original iPad, the Wi-Fi only iPad 2 (A1395) is a tablet computer designed for "browsing the web, reading and sending e-mail, enjoying photos, watching videos, listening to music, playing games, reading e-books, and much more". It is equipped with a 9.7-inch (1024x768, 132 ppi) multitouch "glossy" LED-backlit IPS display and runs a version of the same iOS operating system that powers the iPhone and iPod touch models. As a result it is compatible with thousands of iPad-specific apps as well as most apps for the iPhone/iPod touch, but not Mac OS X apps. It is powered by a custom-designed 1 GHz dual-core Apple A5 "system on a chip", has 16 GB, 32 GB, or 64 GB of flash memory (32 GB and 64 GB options discontinued March 7, 2012, 16 GB discontinued March 18, 2014), front and rear mounted cameras, 802.11a/b/g/n Wi-Fi support, an accelerometer, a three-axis gyroscope, an ambient light sensor, digital compass, a speaker and a built-in mic packed in a 0.34 inch thick, 1.33 pound glass and aluminum case with a black or white front and an aluminum back. The battery life of this iPad 2 is reportedly 10 hours "surfing the web on Wi-Fi, watching video, or listening to music." Compared to the original iPad, major differences for the iPad 2 models include a thinner, lighter case design, faster processors, system-wide mirroring support, and the aforementioned cameras. They also support a new magnetic "Smart Cover" -- available at additional cost -- that protects the screen when not in use and automatically wakes up the iPad 2 when the cover is removed and puts it to sleep when the cover is attached. On March 7, 2012, Apple discontinued the 32 GB and 64 GB configurations and kept the same order numbers for the black and white 16 GB configurations until October 22, 2013, when it reassigned the 16 GB configurations in black and white, order numbers MC954LL/A and MC989LL/A, respectively.