250 mL Breastmilk Bulk Preparation System. Medela's new 250 mL Breastmilk Bulk Preparation System is designed to give NICU professionals a hygienic and convenient solution to breastmilk handling. When used together, the Breastmilk Transfer Lid and Medela's 250 mL container provide a leak-proof connection. Maximize value by purchasing the complete system for preparing bulk breastmilk feeds in the NICU. UOM: 100/CS.