Unlike computer mice, touchpads stay in one place when they are being used. This makes it easy to build them into hardware. They are mostly found on laptop computers because, when the user is travelling, sometimes he or she cannot use a mouse. But most laptops do allow the user is able to attach (connect) a separate mouse. Besides laptops, touchpads are also more and more used on mobile devices with a GUI, including MP3 players (a well-known one being the iPod) and mobile phones (such as the BlackBerry). However, touchpads on today's mobile devices such as smartphones and tablet computers have been replaced with the touchscreen, which is used much like a touchpad except the screen is built into the touch-sensitive surface itself so that no mouse cursor is needed. One can just touch anywhere on the surface to choose what is on the screen at that part.