LOZAEVE 22mm flange inserts to compatible with Spectra S1/S2, Bellababy, Elvie, Paruu R12 P10, Momcozy S9/S10/S12/M1 Wearable, Freemie, Evenflo, Maymom breast pump shields. It will reduce the 27-28mm nipple tunnel down to 22mm. Also fit for Medela (PersonalFit Flex, Harmony, Freestyle, Swing Maxi, Sonata, and Symphony) breast pump flanges/shields, It will reduce the 27mm nipple tunnel down to 22mm. 2pcs each pack. Seamless Compatibility For Optimal Milk Expression: Suitable for nipple diameter 19-21mm(after a pumping session), or measure the circumference of nipple base about 53.38 - 59.66mm before a pumping session. Great solution for small-nippled mothers using large breast shields, Proper nipple tunnel fit is essential for comfort and efficient milk output. It can be compatible with Spectra and Medela (Freestyle, Harmony, Sonata, and Swing-Maxi pumps) and other brands. BPA free, made of silicone material. Durable, clear, and comfortable. This accessory helps breast shields for more effective pumping and maximized milk expression while helping to avoid nipple trauma or irritation. Maintain compatibility with most handsfree bra. You can use most handsfree bra cups with they original 27/28mm detachable shields having this insert inside. During operation, you need to squeeze slightly to make the Insert fully fit with the shield to achieve the perfect effect. This product has a variety of models, which can change the size of the "breast milk channel" on the cover of the breast pump, so as to be suitable for mothers with different nipple sizes, help to improve the breast feeding efficiency and increase the pumping capacity, and make mothers more comfortable in the process of breast feeding.