AAA (NIMH) x2. 100% compatible for Sony batteries - Fully compatible with Sony MDR-DS3000 MDR-IF140K MDR-IF240R MDR-NC200D MDR-RF4000 MDR-RF800R MDR-RF810R MDR-RF811 MDR-RF811R MDR-RF811RK MDR-RF840R MDR-RF850R MDR-RF855R MDR-RF860R MDR-RF925R MDR-RF970R.
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