Portable handheld digital audio recording devices that run the gamut from single track voice memo recorders or field samplers, to complete multitrack studio workstations that fit in your pocket. Many will run on a pair of AA batteries, although more modern versions will usually have built in rechargeable batteries, with options to use USB or an external wall adapter for longer sessions. The majority will also have good quality condensor microphones built in, with more input options available on more advanced models.