An expressing bra (also called a nursing bra/pumping bra) is specially designed to be worn while expressing so you can have your hands free to do other activities. An expressing bra is designed to fit a regular breast pump, which has a funnel-shaped chest piece attached to a bottle. For the Difrax breast pump, an expressing bra is not required. The pump fits completely into the shell of your bra. If you are wearing a breastfeeding bra, you can detach the cup at the front to feed the baby directly. It is not necessary to use a breastfeeding bra with the Difrax pump, but it is possible.