The Medela Swing Breast Pump is a portable, lightweight, single, electric breast pump designed for moms who pump occaisionally. The Swing features 2-Phase Expression® technology, which resembles a baby's nursing rhythm and is effective for breast milk removal. Wonderfully compact breast pump can be taken anywhere, it even fits neatly in your purse! The Medela Swing Breast Pump comes with a belt clip and neck/shoulder strap to make mobile and tabletop pumping easier. The convenient drawstring bag helps keep the breast pump's components organized and clean. Requires four AA batteries (sold separately) for portable use, and includes an AC adaptor.