In the case of the Pronto from Power Practical it's all about speed, as the device can obtain the power for a full charge in just five minutes.
The development team is offering the device in two flavors – the Pronto 5 and Pronto 12. As you can probably guess, the 5 is smaller, coming with a 4,500 mAh battery, while the 12 includes a 13,500 mAh battery. Basically, the smaller one is enough juice to charge an iPhone 5 three times, while the larger model can deliver nine charges.
Speed is the selling point of these devices, but keep in mind ... the Pronto takes five minutes to store the power necessary for a single charge of the phone, but it will take much more than that to actually charge the phone. However, it means users won't be tied to wall outlets for an extended period, which is the main idea. Additionally, both Pronto models fully charge in about one hour, providing them with the juice needed for multiple charges.