Single electric breast pump is the first daily use electric pump with the research-proven 2-Phase Expression® Technology that provides more milk in less time. 2-Phase mimics baby's natural pattern for a better pumping experience and has an adjustable speed and vacuum for efficient use. The Swing™ Breast Pump is lightweight and comfortable with the SoftFit® breast shield. With the included belt clip or shoulder/neck strap, you can even use it on the go. Includes an AC adapter or can operate with four AA batteries which are not included.