This breast pump was designed to use Natural Expression technology, the only research-based breast pump technology that mimics a baby's nursing rhythm. Designed to feel and function as comfortably as natural breastfeeding, the device starts in a rapid suckling to initiate rapid milk flow. Once flow begins, the mother switches to a slower suckling to optimize flow. The ergonomic handle swivels for easy positioning and the pump is compatible with most standard baby bottles, making disposable bags unnecessary.