Most Brother home machines use the SA156 bobbin, a clear plastic bobbin Brother lists as 11.5 mm (7/16 inch) tall. That covers the XM2701, CS7000X, XR9550, SQ9285, HC1850 and the SE and PE embroidery machines. Singer's Heavy Duty line (4411, 4423, 4432, 4452, 4552 and relatives) takes Class 15 transparent bobbins, per Singer's own product pages. Find your model in the chart below. If it isn't there, the manual is the only answer we'd trust.
Where this chart comes from
We didn't build this from bobbin-seller compatibility lists, which tend to claim everything fits everything. The Brother half comes from Brother's SA156 product page, which publishes a "For Use With" list of about 200 models, and from the Consumables pages on Brother's support site for models missing from that list. The Singer half comes from the product pages on singer.com, which state the bobbin class for each machine. All of it was read on October 3, 2026.
This is a spec review: a lookup built from the makers' own pages, not a fit test we ran. How we research.
Brother: which bobbin each model takes
Brother status (current or discontinued) is from Brother's product pages on the same date.
| Model | Bobbin | Source | Brother status |
|---|---|---|---|
| XM2701 | SA156 | SA156 fit list | Current |
| XM3700 | SA156 | Brother support, Consumables | Current |
| LX3817 | SA156 | SA156 fit list | Current |
| GX37 | SA156 | SA156 fit list | Current |
| ST371HD | SA156 | SA156 fit list | Current |
| CS5055 | SA156 | SA156 fit list (as CS5055PRW) | Current |
| CS7000X | SA156 | Brother support, Consumables | Current |
| XR9550 | SA156 | SA156 fit list (as XR9550PRW) and support | Current |
| SQ9285 | SA156 | SA156 fit list | Current |
| HC1850 | SA156 | SA156 fit list | Current |
| CS6000i, CS7000i | SA156 | SA156 fit list | Discontinued |
| JX2517 | SA156 | SA156 fit list | Discontinued |
| SE600, SE625, SE1900 | SA156 | SA156 fit list | Discontinued |
| SE630, SE700, SE725, SE2000 | SA156 | SA156 fit list | Current |
| PE545, PE900 | SA156 | Brother support, Consumables | Current |
| PE800 | SA156 | Brother support, Consumables | Discontinued |
| PE500, PE540D, PE770 | SA156 | SA156 fit list | Discontinued |
| PQ1500SL | SA159 (not SA156) | Brother's SA159 page | Discontinued |
The PQ1500SL is the odd one out. It's a straight-stitch quilting machine, and Brother's SA159 page lists it with Brother's PR multi-needle embroidery machines instead. If you own a PQ-series machine, check your manual before buying SA156 packs.
Brother's support site has the same answer on its own terms. On the quick-set bobbin pages it says: "Use only the enclosed bobbin or bobbins of the same type (part code: SA156, SFB)" and warns not to use bobbins made for other models.
Singer: Class 15 transparent across the Heavy Duty line
| Singer model | Bobbin Singer names |
|---|---|
| Heavy Duty 4411, 4423, 4432, 4452 | Class 15 transparent ("SINGER or INSPIRA branded bobbins are recommended for best results") |
| Heavy Duty 4511, 4523, 4532, 4552 | Class 15 transparent (four in the box) |
| Quantum Stylist 9960 | Class 15 transparent |
| M1500 | Class 15 transparent |
The drop-in bobbin goes in with the thread running counterclockwise, according to Singer's Heavy Duty manuals. Get that wrong and you'll see loops on top of the fabric. Our Singer Heavy Duty problems page has the rest of Singer's fix table. Not sure which Singer model you have? Start with the serial number lookup. Once you have the right bobbin, here's how to load it and thread a Singer.
Other brands (Janome, Juki, Baby Lock and older Kenmore models) aren't in this chart because we didn't verify them. Their manuals name the bobbin in the accessories list near the front.
How to read a bobbin label
Three names float around, and they don't mean the same thing to everyone:
- SA156 is Brother's part number, and Brother gives its height as 11.5 mm (7/16 inch).
- Class 15 is the name Singer uses for the Heavy Duty bobbin. Bobbin sellers often print "Size A / Class 15 / SA156" on the same pack, but that's their claim, not Brother's or Singer's.
- Class 66 is a different bobbin class that some other machines use. We found no Singer or Brother statement that 15 and 66 swap, so treat them as different parts.
What the wrong bobbin does
A bobbin from another machine can still drop in, which is why it's easy to miss. Brother's quick-set bobbin pages tell owners not to use bobbins from other models because the machine won't operate correctly, and Singer's manuals put a wrongly inserted or threaded bobbin behind broken bobbin thread and loops on top. In practice that shows up as loops, a snapped bobbin thread, or a nest that ends in a jam. Brother's tangled-thread and error code pages trace E6, its motor-lock code, to the same kind of tangle. See our Brother error codes page for that one.
Metal is the other trap. Brother's SA156 is clear plastic, and Singer specifies transparent Class 15 bobbins; a metal bobbin isn't what either maker names, even when a seller's listing says it's the same size.
If you've got bunching and the bobbin checks out, the cause is usually upstairs. Our guide to bobbin thread bunching explains why loops under the fabric point to the upper thread.
Which bobbins to buy
Brother SA156 bobbins (10-pack)
The part Brother itself names. It's the second best-selling bobbin on Amazon right now, with over 12,000 ratings and more than 2,000 bought in the past month. Brother's listing points out the security notch for winding and the clear plastic, which lets you see how much thread is left. If your Brother model is on the fit list above, buy these and stop thinking about it.
- Part numberSA156
- Count10
- Materialclear plastic
- Height11.5 mm (Brother)
Why it stands out
- Brother's own part, so there's no compatibility question
- Clear sides show the thread level
Think twice if
- You need dozens of bobbins; generic packs cost less per bobbin
30-pack plastic bobbins for Brother (SA156 style)
For quilters and embroiderers who keep a bobbin wound in every color. The listing says it fits Brother machines that accept SA156 bobbins, and 900 were bought in the past month. These aren't Brother-made, so if you ever see uneven feeding from a bobbin, swap in a genuine SA156 to rule it out.
- Count30
- TypeSA156 style (per listing)
- Materialplastic
Why it stands out
- Three times the bobbins of the Brother pack
- Listing states SA156 fit
Think twice if
- You'd rather stick to Brother's "same type" advice to the letter with genuine parts
New brothread prewound SA156 bobbins (25)
Prewound bobbins save winding time on embroidery machines, where the bobbin thread is usually white and lighter than the top thread. This pack lists itself as Size A, Class 15 (SA156), wound with 90 wt spun polyester, and it has nearly 4,900 ratings. The plastic sides mean you can drop them straight into an SA156 machine.
- Count25
- SizeA / Class 15 (SA156) per listing
- Thread60S/2 spun polyester, 90 wt
- Sidesclear plastic
Why it stands out
- No winding, and the clear sides fit SA156 cases
- Lighter bobbin thread suits embroidery
Think twice if
- You sew garments and want the bobbin thread to match the top color
NGOSEW plastic bobbins for Singer Heavy Duty
The listing names the 4411, 4423 and 4452 directly, and it has close to 1,600 ratings. Singer recommends SINGER or INSPIRA branded bobbins for best results, and these are neither, so treat them as spares. If a Heavy Duty starts looping on top after you switch bobbins, go back to a Singer-branded Class 15.
- Fits (per listing)Heavy Duty 44S, 4411, 4423, 4452, 5511, 5523, 5532
- Materialplastic
Why it stands out
- Listing names the common Heavy Duty models
- Clear plastic, like Singer's Class 15 transparent
Think twice if
- You want the exact bobbin Singer recommends
Three habits that keep bobbins from causing trouble
Wind slowly and evenly. Brother's quick-set pages warn that a badly wound bobbin can loosen the tension and break the needle. Throw out bobbins with cracked or scratched rims, because the thread catches on them. And keep the bobbin area clean: lint under the bobbin case changes how it sits just as much as the wrong bobbin does.
The same model-number check applies to replacement foot pedals: match the part to your exact machine before you order.
The needle matters as much as the bobbin. Check ours against your fabric in the needle size chart, and see the Brother sewing machine comparison chart for each current Brother model's specs.
Bobbin fit from Brother's SA156 and SA159 product pages, Brother support Consumables pages for the CS7000X, XR9550, XM3700, PE545, PE800 and PE900, and singer.com product pages, all checked October 3, 2026. Product details from each Amazon listing on the same date. How we research · Affiliate disclosure