A laptop is a personal computer designed for mobile use and small and light enough to sit on one's lap while in use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device (a touchpad, also known as a trackpad, and/or a pointing stick), speakers, and often including a battery, into a single small and light unit. The rechargeable battery (if present) is charged from an AC adapter and typically stores enough energy to run the laptop for two to three hours in its initial state, depending on the configuration and power management of the computer.