The famous high-end DIY site in China – Chipchell.com reviewed our mobile mini speakers, the writer emphasized the ultra portability of Razer Ferox, including the tiny size, compatible with all devices have 3.5mm audio jack, and the build-in Li-ion battery that provides up to 12hours playback time. He thought Ferox maybe the best choice, if you are having a trip or just out-side there and wanna enjoy a better sound. But he did point out that users can do nothing with the build-in battery when the battery is dead and the warranty expired.