2 Pcs Z55H Replacement Battery for Sony WF-1000X / WF-1000XM4 (Z55H, 3.85V, 70–75mAh) with Adhesive Tool
Product description
The essentials
If your Sony true wireless earbuds are starting to lose charge quickly, a replacement battery is often the most practical fix. This 2 pcs Z55H battery set is listed as a new upgrade (2024) and is aimed at users who want replacement batteries for a range of Sony WF and WI earbud models.
On paper, the key draw is the stated “perfect compatibility” with the original Z55H battery used in models such as the WF-1000XM4, alongside several other compatible ranges. You also get the batteries as a pair, which is useful if one side is lagging or if you’d rather swap both at the same time to keep balance.
That said, replacement batteries aren’t a plug-and-play sort of purchase for everyone. Some people may not have the patience for careful opening and placement, and the usefulness of the included adhesive tool depends on how comfortable you are with the job.
What it’s for
This is a replacement battery kit designed for certain Sony in-ear true wireless models listed in the product description: WF-1000X, WF-1000XM4, WF-1000XM3, WF-SP900, WF-H800, WF-SP700N, WF-XB700, WF-C700N, WF-C500, WI-SP600N and WI-C600N. The intent is straightforward: restore charging performance by swapping out an aging internal battery.
A quick example of the kind of situation this suits: you’re fine for calls at home, but after an hour or so the right earbud starts dropping faster than it used to, or you notice a general decline in time between charges. Swapping both batteries can bring back more consistent everyday use.
Where it stands out
The most important details provided are electrical and identification ones. It’s listed as: - 3.85 V battery voltage - Z55H battery part / product number Z55H (also referenced as CP1254) - Battery capacity is stated as 70mAh in the product title and also 75mAh in the base description, so you may want to double-check the exact listing details for consistency before buying
It also includes an adhesive tool, which is meant to help with the replacement process. For many buyers, that’s the difference between “maybe” and “I can actually get this done”.
What you’ll notice day to day
When these replacements are the right match, the everyday impact is usually about consistency. Newer batteries tend to restore more predictable run time and reduce the feeling that one earbud is “falling behind”. Because this is a two-pack, you’re also less likely to end up with mismatched battery health between left and right.
However, if the underlying issue is something else—like charging contacts, firmware behaviour, or case charging problems—then a battery replacement may not fully fix what you’re seeing. It’s a good option when the battery itself is the suspected bottleneck.
Tech specs
- Type: Replacement battery (Z55H)
- Voltage: 3.85 V
- Capacity: 70mAh (title) / 75mAh (description)
- Part number: Z55H (also referenced as CP1254)
- Actual dimensions: D5.5 x W12 (mm)
- Included: Adhesive tool (as stated in the listing)
Who should buy (and who should skip)
It’s a solid pick if you’ve identified battery wear as the likely cause and you’re comfortable doing a careful internal replacement for the models listed in the description. It also makes sense if you want two batteries ready for either a full swap of both sides or a backup.
It may not suit you if you’re expecting a simple “open and stick” job with no fiddly parts. Replacement work can be fiddly, and the adhesive tool helps, but it doesn’t remove the need for patience and care. Also, if your problem is intermittent charging rather than run-time drop, you may be better starting with a charging case and contact check.
Final verdict
Worth considering if you’re trying to extend the life of compatible Sony earbuds without replacing the whole set. The key is that it’s clearly aimed at Z55H battery swaps for the listed models, comes as a 2-pack, and includes an adhesive tool to support the process.
But don’t treat it as guaranteed magic: it’s not the best choice if you’re unsure whether the battery is really the problem, or if you don’t want to open the earbuds. Also, double-check the capacity details in the listing because the title and description mention different mAh figures.
Quick buying checklist (mini FAQ)
Is this compatible with the WF-1000XM4?
The listing states compatibility with the original WF-1000XM4 battery and includes WF-1000XM4 in its compatible model list.
What voltage is the Z55H replacement battery?
It’s listed as 3.85 V.
Does it come with anything to help with installation?
Yes, the listing mentions an adhesive tool included in the pack.
Why does the capacity look a bit inconsistent?
The title mentions 70mAh, while the base description also states 75mAh. It’s worth checking the exact product details shown on your selected listing to avoid confusion.
Should I replace both batteries at once?
If you want more even performance and you’re already doing the replacement, a two-pack is handy for swapping both sides—just be sure your compatible model matches the listing.