COMPATIBLE WITH: Medela's Pump in Style with MaxFlow technology, Swing Maxi, and Freestyle Flex breast pumps CLOSED SYSTEM: Overflow Protection prevents milk from overflowing into the tubing and motor. Easy to assemble and clean MEDELA AUTHENTIC SPARE PARTS: Quality and performance you can trust. Have an extra set for work or travel, or a replacement for lost or damaged connectors COMFORTABLE DESIGN: Pump in more reclined and comfortable positioning CUSTOMIZED FOR YOU: Works with all PersonalFit Breast Shields and sizes, including the PersonalFit Flex Breast Shields