The specification does not say that the battery is not included. I wasn't expecting to be connected to USB power. Pairing with my headphones is easy and the sound is fine when I plug it into my old MP3 player. However, I probably wouldn't have bought it if I had known there was no battery.
Experience Dynamic Audio with Panasonic SC-UX100 CD & USB Wireless Bluetooth 300W Mini Hi-Fi System Shelf Stereo
19 Review
JBL Horizon Bluetooth Alarm Clock Radio with Multiple Alarms, Soothing Ambient LED Light, Automatic LCD Display, and Dual USB Charging (White, AM/FM Radio)
41 Review
Sony ICFC1TBLACK Alarm Clock Radio
11 Review
Radio receiver Max MR-322 anthracite
14 Review