JBL Eon One One Mk2 Dual Battery Charger

Full Product Description (From the manufacturer)

Play more sets, teach more classes and keep the party going all night long when you extend the performance time of your EON ONE MK2 system with extra batteries. The JBL EON ONE MK2 Dual Battery Charger quickly charges one or two EON ONE MK2 lithium-ion rechargeable batteries; full charge is complete in less than three hours for one battery and less than six hours when charging two batteries.