Caption Power AC adapter fit HP Elitebook 840 G3 notebook,  brand new,  100% compatible with good quality, and free from defects in material and workmanship.   Fit with following laptop: HP Elitebook 840 G3 Specifications: Type:  Power AC Adapter Input Voltage: AC 100-240V~50/60HZ Output Voltage: DC 19.5V 2.31A/3.33A  Max. Output Power:  45W/65W  Connector Size:  4.5*3.0mm (as pictures) Manufacture Guaranty: 12 Months Operate Environment: Please keep the environment cool and dry! Tips for how to choose the right power adapter/charger for your laptop:  Please make sure the power adapter's Output & Connector Size are matching your original Adapter's. Output Voltage and polarity must match with your old adapter.  Output Current is not as critical as output voltage, you could select either same or higher output current adapter.  If the previous three notes are the same as your adapter, you can be sure our adapter is compatible, even if your model is not listed. You can check with the Output Voltage and Output Current on the label of your original charger or the bottom/back of your laptop. As to the polarity (connector size) you can measure it or compare with ours.If you are not sure, please don't hesitate to contact us.