Rechargeable Battery BP-HP550-11 For Sony Headphones MDR-RF | eBay
Sony BP-HP550-11 Replacement Battery Ni-MH, 2.4 Volt, 700 mAh - Ultra Hi-Capacity - Replacement for Sony MDR-RF810/840/850/860/925/970/4000 Rechargeable Battery - Walmart.com
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