ZenBook is a family of ultrabooks – low-bulk laptop computers – produced by Asus. The first ZenBooks were released in October 2011, and the original range of products was amended and expanded during 2012. Models range from 12-inch laptops featuring power efficient components but lacking connectivity and having only integrated graphics processors, to 15-inch laptops with discrete graphics processing units and optical disc drives. Most (though not all) ZenBooks use Intel Core ultra-low-voltage processors and Nvidia GPUs when integrated graphics are not used. Asus introduced new models with touch screens to take advantage of Windows 8 after its release in late 2012. Most models drew comparisons to the MacBook Air. The ZenBook mainly competes against computers such as Acer's Aspire, Dell's Ins