This external battery has compact size, large capacity, is easy to carry, Fits most laptop computers which have 16 - 19V DC input jacks , or with original battery pack voltage 10.8V - 14.8V. Lets your notebook run 2-3 hours more. Capacity: 4000mAh Running time: 2- 3 hrs depended on laptop model Battery Chemistry: Lithium Ion (Li-ion) Input: DC16.8V/1.5A Output: 16V and 19V DC switch able according to your battery. ( if original laptop battery is 10.8V , outout to 16V, if laptop battery's voltage is 14.8V, 19V) Dimension: 155x100x23 mm Weight: 560g Switching Power Supply/ Charger Input: 100-240V AC 50/60Hz, worldwide power support Output: 16.8V DC 1500mA Dimension: 120x59.5x38 mm Weight: 287g Detailed Description: Charging current is 1.5 A, charge time is about 3.5 hours. Constant charging current ( 1. 5 A) with constant voltages will apply in initial charging. The charging current will change to ( 1. 0 A) when battery is close to full. This charging method will ensure the battery pack to get fully charged with longer service life. Power will be cut-off automaically when battery is full. It is a smart and safe charger The external battery pack has low voltage alarm. If the voltage of battery is lower than 13 Vs, an alarm rings for 10 seconds. 6 LEDs will indicate battery capacity level at 25% - 50% - 75% - 100%, as well as if battery is charging (CH) and if the battery if fully charged ( FU). All indicator lamps can be turned on to show battery capacity status or turned off to save energy Important Notice: You may need a DELL connector, please check the following picture and dimensions carefully to make sure it can fit your Dell Notebook. tHE Dell connector can be bought with this battery at extra cost, please make sure you the 'Add Dell connector' option before checking out. Please double check the below before purchasing the battery pack If your computer power supply is between 16V DC - 19V DC, if yes, you may buy