Which pumps does the 21mm Spectra flange fit?

The 21mm flange fits all Spectra pumps with wide-mouth connections, including the Spectra S1, S2, and 9+. The included valve and membrane are compatible with both Spectra and Medela pump systems.

How do I know if 21mm is the right flange size for me?

A 21mm flange may be the right size if your nipple measures about 17–19mm before pumping. Using the correct flange size helps reduce pain and can improve milk output. If the flange feels tight, rubs, or causes blanching, you may need a different size.

How should I clean and sterilize the flange and duckbill?

Wash all parts in warm, soapy water and rinse well. You may also sterilize the flange, valve, and membrane using steam bags, a sterilizer, or boiling water according to pump-part guidelines.

Can this flange help if my current Spectra flange feels too big or too small?

Yes. Switching to a 21mm flange can help if the standard 24mm Spectra flange feels too large, causes discomfort, or reduces milk output. A better-fitting size often improves suction seal and comfort during pumping.

21mm Spectra Flange - 1 pack

$9.00

This is a single piece for one side (NOT a two pack). Fits Spectra pump, wide base and comes with an extra valve and membrane (duckbill) that works with the Spectra and Medela products.

Quantity:

This is a single piece for one side (NOT a two pack). Fits Spectra pump, wide base and comes with an extra valve and membrane (duckbill) that works with the Spectra and Medela products.

21mm Spectra Breast Flange – Single Breastshield With Valve & Membrane (1-Pack)

If you pump with a Spectra and need a precise 21mm fit, this single breastshield is designed to give you better comfort, stronger suction, and more efficient milk expression. This listing includes one flange for one side (NOT a two-pack), plus an extra duckbill valve and membrane that work with both Spectra and Medela pumps.

The 21mm size is one of the most commonly recommended flange sizes for parents who find the standard 24mm too large or uncomfortable. A better fit can reduce nipple swelling, tugging, and friction, and may help improve milk output by creating a more secure seal.

This flange fits all Spectra wide-mouth pumps, including the Spectra S1, S2, 9+, and Synergy Gold, and works with Maymom-compatible wide-base parts. Made from BPA-free, food-grade plastic, it’s durable, easy to clean, and designed for safe daily pumping.

What’s Included

• One 21mm flange (single breastshield for one side)
• One duckbill valve
• One membrane/backflow piece
• All components made from BPA-free, food-grade plastic

Why Parents Choose 21mm

• Helps reduce pain and nipple trauma
• May improve suction and milk output
• Offers a more comfortable, secure fit
• Ideal for exclusive pumpers or parents who pump at work
• Great for replacing a single flange or customizing fit per side

Frequently Asked Questions

Is this a single flange or a two-pack?

This product is one single 21mm flange designed for one pumping side. It is not a two-pack, which makes it easy to replace only the side you need.

Does the 21mm flange fit all Spectra pumps?

Yes. It fits the Spectra S1, S2, 9+, and Synergy Gold, along with Maymom-compatible wide-neck systems. It works with standard Spectra wide-base bottles and accessories.

How do I know if 21mm is the right size?

Most lactation professionals recommend choosing a flange based on:
nipple diameter + 1–3mm after pumping.
Many parents choose 21mm when:
• the 24mm flange feels too large
• the nipple is being pulled too deeply into the tunnel
• pumping causes pinching or swelling
• milk flow seems inconsistent or low

If any of these apply, the 21mm size may be a better fit.

What’s included with this flange?

You receive one 21mm flange, one duckbill valve, and one membrane. The valve and membrane work with both Spectra and Medela pumps.

Is the flange material safe?

Yes. It’s made from BPA-free, food-grade plastic that is heat-resistant and safe for milk collection.

How do I clean the flange and included parts?

Wash all components in warm, soapy water and rinse well. You may also sterilize using boiling water, steam sterilizers, or microwave steam bags according to your usual pump-part routine.

Can switching to 21mm improve output?

For many parents, yes. A properly fitting flange often leads to:
• better suction
• more efficient letdowns
• improved milk flow
• less discomfort and friction

A correct fit can make pumping more comfortable and productive overall.

Ideal For

• Parents needing a smaller, more accurate fit
• Exclusive pumpers
• Work pumping setups
• Replacing a single flange
• Building a backup kit for home, work, or travel