TAU is the best 3-in-1 power bank, it fits the iPhone (Apple), Micro USB, and USB-C. It’s the smallest power bank in the world, so you can attach it to your key chain, and comfortably use it in your daily life. It’s the best portable power bank and alternative to your regular, heavy battery charger. TAU is featured with USB-C, Lightning, and Micro USB cables, and is compatible with virtually every portable device. Thanks to its proprietary dock, charging it is as easy and seamless as hanging your keys once you get home.