Flange Inserts vs New Flanges: Which Should You Buy?

Quick answer

Buy flange inserts when your current flange is the right style but the tunnel is too large, and buy a new flange when you need a different flange size or a replacement for a worn or damaged flange. If you already own a 24mm flange, inserts are usually the cheaper way to test a smaller fit; if you do not own a compatible flange, start with the flange itself.

What each option actually changes

A flange is the funnel-shaped part that sits against your breast and forms the tunnel your nipple moves through. Inserts are separate pieces that fit inside an existing flange tunnel to reduce its effective size. That means inserts do not replace the flange; they modify it. If your flange is cracked, warped, or no longer seals well, an insert will not fix it.

This is why the decision is not really inserts versus flanges in the abstract. It is about whether your current flange is structurally sound and correctly sized. If it is sound but too large, inserts are the lower-cost adjustment. If it is the wrong size at the tunnel or needs replacement, a new flange is the direct fix.

When to buy flange inserts

Choose inserts when you already have a compatible flange and the only problem is that the tunnel is too wide. BabyBuddha's 21mm and 13mm flange inserts are designed to fit wearable breast pump and 24mm flanges, so they work as a sizing adjustment inside a flange you already own. They are also useful if you are between sizes or want to test a smaller fit before committing to a different flange setup.

Inserts are not a universal fix. They are made for specific flange compatibility, so check that your flange accepts them before buying. If your flange is not compatible, or if you need a different flange style entirely, inserts will not help.

When to buy a new flange instead

Buy a new flange when you need a different tunnel size that inserts cannot provide, when your current flange is damaged or worn, or when you want a fresh replacement rather than an add-on. A 24mm flange is a common starting size, and if it is too large, inserts can reduce it. But if you need a size outside what inserts offer, or if the flange itself is the problem, replace the flange.

Replacement timing matters too. Silicone parts that contact milk and air wear over time. BabyBuddha recommends replacing the silicone diaphragm every 8-9 weeks, especially with multiple daily pumping sessions. If you are replacing worn parts, check the flange at the same time so you are not pairing a new diaphragm with a flange that no longer fits or seals properly.

How to check compatibility before you buy

Compatibility is the step most people skip. Inserts are sized to fit specific flange tunnels, and a 21mm insert is not the same as a 21mm flange. The insert reduces the effective tunnel size of the flange it sits inside. So if you own a 24mm flange, a 21mm insert gives you a smaller effective fit without buying a whole new flange.

Before ordering, confirm three things: the flange you own, the tunnel size you actually need, and whether the insert is listed as compatible with your flange. If any of those are unclear, the safest purchase is the flange that matches your measured size, because it removes the compatibility question entirely.

Cost and convenience trade-offs

Inserts are generally the lower-cost way to adjust fit because you are buying a small accessory rather than a full flange. They are also easier to swap if your size changes. The trade-off is that they add a part to clean and keep track of, and they only work with compatible flanges.

A new flange costs more than an insert but gives you a dedicated part with no added compatibility layer. If you are replacing a worn flange anyway, buying the flange in your size is simpler than buying a flange plus inserts. If you are experimenting with size, inserts let you test a fit with less commitment.

Decision rules: inserts or a new flange?

• You own a compatible flange and the tunnel is too large: Buy flange inserts. They reduce the effective tunnel size of your existing flange, which is usually cheaper than replacing the whole flange. Check that your flange is listed as compatible before ordering.
• You do not own a compatible flange, or your flange is worn or damaged: Buy a new flange. Inserts modify a flange; they do not replace a missing or failing one. If the flange itself is the problem, an insert will not fix it.
• You are between sizes or unsure which size you need: Start with the flange that matches your measured size, or use inserts only if you already have a compatible flange to test with. A dedicated flange removes the compatibility question.
• You are already replacing worn pump parts: Replace the silicone diaphragm on the recommended 8-9 week schedule and inspect the flange at the same time. Pairing a new diaphragm with a worn flange can undo the benefit of the replacement.

Product facts to guide your choice

• Flange Inserts – 21mm (2-pack) for Wearable Breast Pump and 24mm Flanges: 21mm flange inserts are designed to help moms achieve proper alignment, improved comfort, and optimized milk expression when using BabyBuddha pumps, and they fit wearable breast pump and 24mm flanges. If you already own a compatible 24mm flange and need a smaller effective tunnel, this insert is the lower-cost adjustment rather than buying a new flange.
• Flange Inserts – 13mm (2-pack) for Wearable Breast Pump and 24mm Flanges: 13mm flange inserts are designed for proper alignment, improved comfort, and optimized milk expression, and they fit wearable breast pump and 24mm flanges. This is the smaller insert option, so it matters if your measured size is well below what a 24mm flange provides and you want to keep using your existing flange.
• 24mm Flange (1-pack) for Wearable Breast Pump ONLY: The 24mm flange is a soft, precision-engineered flange for a secure, comfortable fit, and it is compatible with flange inserts ranging from smaller sizes if you need a smaller fit. This is the flange to buy if you do not already own a compatible flange, or if your current flange is worn or damaged and inserts alone will not solve the problem.
• Silicone Diaphragms (FOR FLANGES ONLY): Silicone diaphragms, also known as backflow protectors, keep milk and air from flowing back up the tubing, and BabyBuddha recommends replacing them every 8-9 weeks, especially with multiple daily pumping sessions. If you are already replacing worn parts, check the flange at the same time so you are not pairing a fresh diaphragm with a flange that no longer fits or seals correctly.

Who should choose which

Best for flange inserts

• Pumpers who already own a compatible 24mm flange and need a smaller effective tunnel size
• Anyone testing a smaller fit before committing to a different flange
• Pumpers who want a lower-cost sizing adjustment

Not for flange inserts

• Pumpers who do not own a compatible flange
• Anyone whose flange is cracked, warped, or no longer seals properly
• Pumpers who need a tunnel size that inserts do not provide