ThinkPad Stack is a versatile innovation that combines four popular accessories into one. A power bank, a wireless router, an external hard drive and a Bluetooth speaker, all designed into a stack form factor which helps you make the most efficient use of space. Its modular design gives you the flexibility of bringing only the ones you need. Multiple combination options make it more than meets the eye. ThinkPad Stack Bluetooth Speaker, the mobile conferencing and entertainment tool.Bluetooth 4.0 pairing Embedded Li battery for 8 hours of playback Noise-reducing technology, D notes solution to provide premium sounds Pogo interface, can be charged by ThinkPad Stack 10,000 mAh power bank