HP (K0Q39AA) 7.4 mm to 4.5 DC Dongle

Simply attach one end of the dongle to your existing HP EliteBook 840 Business Notebook or HP ZBook 14 Mobile Workstation power adapter and connect the other end to your HP CO06XL Long Life Battery.
There’s no need to carry separate power cords — you can retrofit your current 7.4 mm power adapter to a 4.5 mm power adapter.