The fourth-generation iPad was marketed by Apple Inc. as iPad with Retina display, and colloquially referred to as the iPad 4. This model featured new and upgraded components such as the Apple A6X chip, and later the Lightning connector. The fourth-generation iPad was praised for its hardware improvements as well as the Retina display (also featured in the iPad 3). The iPad 4 comes with several pre-installed applications, including Siri, Safari, Mail, Photos, Video, Music, iTunes, App Store, Maps, Notes, Calendar, Game Center, Photo Booth, Contacts. Like all iOS devices, the iPad 4 syncs content and other data with a Mac or PC using iTunes. This model also an optional iBooks application, which displays books and other ePub-format content downloaded from the iBookstore.