Breast Pump Kit (Breastshield 19mm, Xs) for Medela Pump in Style Advanced Breastpump. Include Replacement Tubing for Pump in Style, 2 One-piece Breastshields (Replace Medela Personalfit), 4 Valves, and 8 Membranes. Replace Medela Personalfit Connector and Breastshield. Medela Xs 21mm Breastshield, Medela Valve, Medela Membrane. Suitable for Pump-in-style Released After July 2006.