Flange 10PCS 21mm＋24mm 21mm＋24mm 21mm 2＋24mm 2 21mm 2＋24mm 2 21mm＋24mm. LUXEMUM shield covers and flange inserts help you find the perfect fit for your nipples. The size of the LUXEMUM flange insert is crucial for comfortable and efficient breast pumping.