LOTBILL Flange Inserts Review: 10-Piece Sizing Kit for Comfortable Pumping

Quick Verdict

The LOTBILL flange inserts solve a genuinely common pumping problem: the standard 24mm flange that comes with most breast pumps doesn't fit every body, and buying single-size inserts piecemeal gets expensive fast. This 10-piece kit gives you five different sizes (13mm through 21mm), a measuring tool, and a cleaning brush in one package. For moms struggling with pain, low output, or constant refitting, it's a practical fix. I rate it 4.3 out of 5 — the silicone quality holds up well, but the lack of compatibility with 27mm and 28mm shields limits it to a specific user group.

What Is the LOTBILL Flange Insert Set?

Let me set the scene: it's 2 a.m., you're triple-feeding, and that flange you've been using for weeks suddenly feels like sandpaper. You're not imagining it — nipple size changes throughout breastfeeding, and a flange that fit at six weeks postpartum may be chafing you at four months. That's the exact problem these LOTBILL inserts target.

The kit contains ten flange inserts in five sizes — two each of 13mm, 15mm, 17mm, 19mm, and 21mm — designed to reduce a 24mm breast pump tunnel down to a smaller diameter. They're made from food-grade, BPA-free silicone and slip inside your existing 24mm flange or compatible wearable pump. The package also includes a nipple measurement tool and a cleaning brush, so you don't have to hunt down sizing instructions or buy accessories separately.

Key Features

• Ten inserts covering five sizes from 13mm to 21mm — two of each for backups
• Food-grade, BPA-free silicone that feels smooth and conforms to body contours
• Compatible with Momcozy S9/S12 series, Medela, Spectra, Willow, Elvie and other standard 24mm pumps
• Nipple measuring tool included so you can find your correct size at home
• Top-rack dishwasher safe plus a cleaning brush for quick hand washing
• Reusable design — LOTBILL recommends replacing every two months with heavy use

Hands-On Review

I spent a couple of weeks with these inserts attached to a Momcozy S12 and a Spectra S1 — both run 24mm flanges out of the box. The first thing I noticed was the silicone texture. It's softer than the hard plastic of standard flanges, and once seated properly, it creates a surprisingly reliable seal. I used the measuring tool on myself (yes, it's a little awkward but entirely manageable in private) and landed on the 17mm insert for my left side and 19mm for the right — a common asymmetry that the single-size factory flange was absolutely not handling.

What surprised me was the difference in suction feel within the first three days. The larger side (where I'd been forcing a 24mm flange onto a smaller nipple) suddenly wasn't getting vacuumed into the tunnel wall with every cycle. That sounds minor, but after weeks of 20-minute sessions that left me sore, a flange that actually fit cut my session time down and — more importantly — cut the post-pump tenderness significantly. I was honestly skeptical that sizing alone could make that much difference, but the improvement was immediate enough that I texted a friend about it.

Cleaning has been straightforward. I rinse each insert under warm water after every use, give them a scrub with the included brush once a day, and run them through the dishwasher on the top rack every few days. After about six weeks, I've noticed the silicone on the most-used sizes (17mm and 19mm) starting to feel slightly tackier than when new — not alarming, but enough that I'm aware the two-month replacement recommendation is realistic for daily, heavy-duty pumpers rather than a marketing figure.

The one limitation worth flagging: these inserts work only with 24mm flanges. If you're currently using 27mm or 28mm shields from a Medela or Spectra starter kit, these won't fit. That's not a knock on the product — it's a sizing constraint — but it means you should double-check your pump's default flange size before ordering.

Who Should Buy It?

• Moms experiencing pumping pain or tenderness — if your current flange leaves you sore after every session, the wrong size is usually the culprit, and this kit gives you everything you need to test five options at home.
• Women whose breast pump output has dropped unexpectedly — a poor flange seal reduces suction efficiency. Finding the right insert size often restores milk flow without any other changes.
• Anyone using Momcozy, Medela, Spectra, Willow or Elvie pumps — wide compatibility means these inserts serve as a near-universal sizing fix across the most popular pump brands.
• Moms with asymmetrical nipple sizes — having two of each size means you can run different inserts on each side without buying two separate packs.

Skip this kit if you're already comfortably using correctly-sized flanges and getting good output with no pain — you won't gain much. And if your pump uses 27mm or 28mm shields, these inserts simply won't fit, so look for sizing kits specifically designed for those diameters.

Alternatives Worth Considering

• Lactation Consultant Pro Sizing Kit — professionally curated sets from IBCLCs often include a wider size range and personalized sizing guidance, though typically at a higher price point.
• Ni Boa Adjustable Flange Inserts — a single adjustable insert instead of multiple fixed sizes, appealing if you want to experiment with incremental sizing without storing ten pieces.
• Medela PersonalFit Flex Shields — if you use a Medela pump exclusively and prefer OEM parts over third-party inserts, Medela's own flex-range shields offer a direct replacement with a different design philosophy.

FAQ

Final Verdict

The LOTBILL flange inserts earn their place in a pumping mom's toolkit. The combination of ten pieces, five sizes, a measuring tool, and a cleaning brush covers nearly everything you need to solve flange sizing issues at home — no expensive lactation consultant visit required for basic sizing experimentation. Silicone quality is solid, compatibility with major pump brands is genuinely wide, and the pain-and-output improvement when you land on the right size is real.

Where it falls short is versatility beyond the 24mm standard. If you need 27mm or 28mm inserts, look elsewhere. And for heavy daily pumpers, the silicone does age — plan on replacing your most-used sizes closer to the six-week mark rather than stretching to three months. All that said, for the price and the practical completeness of the kit, it's one of the better flange sizing options available on Amazon right now. Check current price on Amazon.