Maymom Pump Part 1x Flange (21mm) 1 Valve 1 Tubing 1 Backflow Protector Compatible w Spectra S2 Spectra S1 Pump, Not Original Spectra S2 Pump Part Replace Spectra 20mm Flange Valve Backflow Protector

• SUITABLE FOR MOTHERS BORN WITH TWO NIPPLES OF DIFFERENT SIZES: Not Original Spectra Parts. Incl 1 Flange (21mm), 1 Valve, 1 Backflow Protector and 1 Tubing. Why selling only ONE-side? Not every mother was born with two nipples of the same size. With this listing, a mother can buy one size of pumping kit for her individual nipple.
• INTERCHANGEABLE WITH SPECTRA PARTS. All parts are interchangeable with Spectra Pump Parts of Spectra S1, Spectra s2, spectra s1plus and spectra s2plus. Can be used with Spectra flange, Spectra backflow protector, Spectra valve, and Spectra tubing. The flanges can only connect to WIDE MOUTH bottles like spectra bottle (wide mouth version), avent bottle, Motif Luna bottle and Maymom wide mouth bottle.
• WORK WITH WIDE-MOUTH BOTTLES ONLY. Use this kit with Spectra bottles, Avent bottles, and Maymom wide mouth bottles. DOES NOT work with OTHER WIDE NECK BOTTLES. CLOSED SYSTEM. No contact between milk and tubing.
• DIFFERENT FLANGE SIZE AVAILABLE: 15mm, 17mm, 19mm, 21mm, 24mm, 25mm, 27mm, 28mm, 30mm, 32mm. Refer to size selection guide in product photo to choose the right size for you.
• IN RETAIL PACK. All parts can be sterilized with water steam or boiling water. Do not contain any BPA. Tested by independent labs for safety.

Why selling only ONE-side? Not every mother was born with two nipples of the same size. A mother can buy one size of pumping kit for her individual nipple here. This product is made by Maymom to fit spectra's S1/S2 pumps in addition to spectra 9 and spectra M pumps. It also fit the newest spectra s1plus and spectra s2plus pumps. It is known that using the correct size of flange in breastmilk pumping is the most important factor in achieving comfort and efficiency. Every mother was created differently. One or two sizes can't fit all. That is why Maymom develops more than 12 sizes of flanges spanning from 13 mm up to 36 mm to fit the average mothers and those mothers who need special sizes (e.g. 13, 15, 17, 36 mm). For pumping comfort, measure your nipple diameter first (do it 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, which is measured AFTER a pumping session. There are improvements of Maymom flange over the original spectra design - 1. In addition to Spectra's duckbills, you can use Maymom duckbills or Maymom valve/membrane system with Maymom flange. 2. In addition to fitting Spectra's backflow protector, you can use Maymom long stem, as well as short stem backflow protectors. You can also use Maymom tubing connector (sold separately e.g. ASIN B0033B9CZ2) to connect this flange to many other popular breastpumps on the market. Content of the kit: Wide Mouth Flange x1 Tubing x1 Backflow protector x1 Duckbill valve x1 NOTE: Bottles and Nipples are not included in this listing. About Maymom 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! Disclaimer: Maymom is an independent company. Spectra is a trademark of Uzinmedicare, Korea. Maymom is not affiliated with Uzinmedicare.