 "GoPro Dual - battery charger USB" " GoPro USB AHBBP301 Digital Camera Accessories CDWG.com
"Conveniently charge two GoPro Li-ion batteries simultaneously with the dual battery charger. Featuring USB compatibility, you can power it with most standard USB chargers, the GoPro wall or auto charger or a computer. Dual LED indicator lights display the charging status of both batteries: in process (amber) and fully charged (green)." 
 "GoPro Dual Battery Charger + (for HERO4) - AHBBP-401"@en AHBBP-401 Filmtools"@en
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Charge two HERO4 batteries simultaneously
Power it with most standard USB power adapters, the GoPro Wall or Auto Charger, or a computer
Dual LED indicator lights 
Includes a spare 1160mAh lithium-ion rechargeable battery 
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