The iPad is a 9.7-inch touchscreen tablet computer that runs a version of the iPhone operating system. It allows existing apps to expand to its larger screen size and newer apps can be designed specifically for the iPad. Reviews of the iPad note its usefulness for productivity and education due to its large screen and thousands of available apps. While affordable starting at under $1000, some downsides are its built-in battery that cannot be replaced and lack of features like an HDMI port or GPS. However, its thin, lightweight design makes it portable and useful for activities like reading electronic books without back pain.