Medela Breast Pump Parts - FlexMedela Breast Pump Parts Flex Creates a new pumping experience with a softer feel and better support for all breast shapes. Helps increase milk production by over 11. 8% with greater comfort, thanks to the new Flex technology featuring a 105 angled opening. Suitable for all breast shapes, including mothers who have had breast augmentation (while standard pump flanges typically have a 90 opening).