21mm Flange Full Pump Parts Set

A comprehensive, drop-in replacement set for Spectra S1, S2, 9 Plus, and Synergy Gold pumps. Contains: 21mm silicone flange (inner diameter 21mm, outer 42mm), duckbill valve, backflow protector, 30cm tubing, and 150ml bottle. All parts made from platinum-cure silicone — odourless, translucent, and resistant to yellowing. Weight: ~180g. Bottle features permanent ml markings; flange thickness: 2.3mm; tubing inner diameter: 4mm. The 21mm flange suits users with narrower nipple bases, reducing drag and improving seal stability — especially noticeable during double pumping or extended sessions. Duckbill valve exhibits minimal hysteresis (lag between vacuum application and opening), sustaining rhythm consistency. Backflow protector uses gravity-assisted condensate pooling to intercept moisture before it reaches the pump head — requiring no user intervention beyond regular washing. Tubing bends smoothly without kinking, even when coiled in compact pump bags. Bottle neck geometry matches Spectra’s proprietary threading for leak-proof sealing. All components are designed for ≥300 cleaning cycles without measurable degradation in elasticity or vacuum retention — verified via accelerated ageing tests simulating 12 months of UK household use.