Easy operation: There is a switch at the bottom of the product, so press it when using it. Check the battery level before use. (Power supply: 2 * AAA battery) | Volume up by 4x: You can increase the volume of AV devices such as mobile phones, tablets and CD players by 4x. It can support music, movies, video chat, car navigation, etc. | If you have any questions or problems during use, please feel free to contact us. Sashimi ─ 扦 î„ 毪 韦 å | Enjoy when connected: Adopts 3.5mm plated plug, compatible with major equipment on the market. It can be applied to most mobile phones, tablets, CD players, car navigation systems, MP3s, MP4s, and other AV devices, and can be enjoyed by connecting. | High Sound Quality Mini Portable Speaker Smartphone Speaker PC Speaker 3.5 MM Audio Laptop / Tablet PC / Smartphone USB Charging Subwoofer Durable and Nice