The WULF 4 Portable Power Pack is a powerful and fully implemented powerbank with a stylish flashing battery indicator, torch function and 2 built-in lithium batteries (4000mAh/3.7V). With the WULF 4 Power Pack, you will now be able to charge your Smartphone, Tablet, Digital Camera, GPS... and even your HIK Vulkan Thermal Monocular (and similar LRF, Night Vision and Thermal devices). Modern, sleek, easy-to-use, and with the included 1m USB/micro USB charging cable, dead batteries in the field will be a thing of the past. Specs WULF 4 Portable Power Pack Battery: 2x Built-In Lithium (4000mAh/3.7V) Input: 5V-1A Output: 5V-2.1A LED Torch: 1x USB Port: 1x Micro USB Port: 1x Material: Plastic Length: 10.00 cm. Width: 4.50 cm. Height: 2.60 cm. Weight: 135.00 g. When you divide the power of the PowerCharger (mAh) by the capacity of the battery in your mobile device (mAh), you know approximately what percentage or how often you can charge your mobile device.