Features:  1) Special design for enjoying music in winter  2) Foldable and portable design  3) Built-in Hi-Fi compact speaker  4) Can be used as ear-warmer after built-in speaker taken out easily  5) Advertisement or logo is available on the side of the wool cover 6) Speaker size: 40mm x 2  7) Output: 0.5W 8) Impedance: 8 ohms