Size 10 (yellow) vs Size 312 (brown)
Sizes 10 and 312 are the two smallest mainstream hearing aid batteries, both 1.45 volt zinc-air cells 3.6 mm tall. They differ in diameter: the 10 (yellow tab) is 5.8 mm across with 90 to 100 mAh, while the 312 (brown tab) is 7.9 mm with 160 to 180 mAh.
| Size 10 (yellow) | Size 312 (brown) | |
|---|---|---|
| Chemistry | Zinc-air | Zinc-air |
| Voltage | 1.45 V | 1.45 V |
| Diameter | 5.8 mm | 7.9 mm |
| Height | 3.6 mm | 3.6 mm |
| Capacity | 90-100 mAh | 160-180 mAh |
| Also sold as | PR70, ZA10, 10A, DA10 | PR41, ZA312, 312A, DA312 |
The size 10 exists for the tiniest hearing aids, the completely-in-canal and invisible-in-canal styles that vanish into the ear. That miniaturization costs runtime: three to seven days per cell against the 312's three to ten in the slim receiver-in-canal aids it powers. The two do not interchange in either direction; the wide 312 cannot enter a size-10 door, and the narrow 10 rolls around uselessly in a 312 bay.
People upgrading or switching aids often have a drawer of the old size, which unfortunately has no use in the new device. Tab colors prevent purchase mistakes: yellow is always 10, brown always 312, in every brand. Both benefit from the standard zinc-air ritual of peeling the tab and waiting a minute before closing the battery door.
If short battery life on size 10 frustrates you, raise it during your next fitting. Modern size-312 and rechargeable aids have closed much of the size gap, and audiologists can often match an in-canal fit with a longer-running platform.