<b>Content of the kit: </b> <br>Shield x 2<br> <b>NOTE</b>: Base connectors are <b>not</b> included in this listing. <br>This listing contains ONLY shields, NOTHING else. NO flange connectors are included. If you have a spectra pump, you need to purchase a wide-mouth flange connector to make up a flange. The connector is placed under the same group of listing for purchase (Connector ASIN: B07WD385MM) <p>This product is made by Maymom for Spectra users, not OEM parts. Compatible with Spectra S1, Spectra S2, Spectra 9 Plus pumps. It is acknowledged that flange (breastshield) size plays an essential role in pumping comfort and efficiency. Maymom develops 11 sizes of shields spanning from 13 mm up to 32 mm to fit the average mothers and those in need of special sizes (e.g. 13, 15, 17, 19 mm). <p> Maymom shield size refers to the INTERNAL DIAMETER (ID) at the ENTRY point of the tunnel where the nipple will go. For pumping comfort, measure your nipple diameter AFTER a pumping session, and then use the size selector of this listing to choose the size that is 1-2 mm LARGER than your nipple diameter as a starting point. Unfortunately, the best fit will never be discovered until you really try it out. That's why the two piece design is more economical for you to find the RIGHT fit. <p><b>About Maymom</b><br> Maymom is specialized in developing breast pump parts that can work with many name brand pumps on the market. The value of Maymom is to care for each mom! <p><b>Disclaimer: </b><br> Maymom is an independent company. Spectra is a trademark of Uzinmedicare, Korea. Maymom is not affiliated with Uzinmedicare.