Medela breast pumps all have a two phase system that mimics the babies natural suction rhythm. Fast and light pumping stimulates let-down first, then slower, deeper pumping optimizes the milk flow, for more milk in less time. The "Freestyle" is a light and portable double pump that you can pump hands free with the attachment kit that comes with it. The Pump In Style is another tried and true double breast pump. The Swing Breastpump is a great single pump. The Harmony is a manual 2 phase pump.