The second-generation iPad (marketed as iPad 2), is a tablet computer designed, developed and marketed by Apple Inc. Compared to the first iPad, as the second device in the iPad line it gained a faster dual core A5 processor, a lighter build structure, and was the first iPad to feature VGA front-facing and 720p rear-facing cameras designed for FaceTime video calling. The device was available initially with three storage sizes, 16, 32 and 64 GB and two varying connectivity options, Wi-Fi only or Wi-Fi and cellular. Each variation of the device is available with either a black or white front glass panel. However, upon the release of the 3rd generation iPad, only the 16 GB variation with two connectivity options and two front color options was available. Apple unveiled the device on March 2, 2011. Upon the announcement of the second-generation iPad, the original model of the iPad was discontinued. Sales of the iPad 2 online and at retail stores began in the United States on March 11. It was then released in 25 other Oceanian, North American and Western European countries on March 25 and released in eleven Asian countries as well as one African country on April 29. Subsequently on May 6 and 27, the device was released in three South American, six Eastern European and three Asian countries. The device received mixed to positive reception from various blogs and publications. Although it was praised for its hardware improvement, such as the new Apple A5 chip, the software restriction on the second-generation iPad and iOS in general drew criticism from various technology commentators. The device sold well in its first month of sales with 2.4–2.6 million units sold and 11.12 million units were sold in the third quarter of 2011. A popular product, with a lower screen resolution and performance than the two Retina models that followed it but a lighter build and longer battery life, it remained in the Apple line-up as an entry-level iPad model for three years until March 2014, latterly with a silent upgrade to a die-shrunk version of the A5 processor. Its basic design formed the core of the first iPad mini, which had the same screen pixel count and similar features at a smaller size. The iPad 2 has been able to run six major versions of iOS, from 4 to 9, the first and only iOS device to be able to do so.