If you have low milk supply, a premature baby, a baby that is unable to breastfeed, or if you have twins and need to produce double quantities then renting a hospital grade breast pump is the most effective way to express your breastmilk.  The Carum breastpump is a closed system where you can single or double express as desired.  It has a sensitive setting for tender breasts or nipples, a timer, plus a dimmer for those late nights when you are expressing.