This USB charging device is great and lasts for ages; providing multiple charges to iPhone/iPad etc. The only downside is the weight of it. It's really heavy. Before getting such a big one (15,000mAh) think about what you'll need it for. If it's just to keep in your bag for emergencies, then it might be better to consider a smaller capacity (and therefore lighter) option.
This is perfect for run and gun. Quickly position height and tilt/pan smoothly to catch the action as it happens. In the past I've used a tripod, so the comparatively small footprint is great. I don't get a sore back after shooting with this for a day, like I do with a shoulder rig.