The portable headphone amplifier FiiO A1 significantly enhances music playback and increases performance when connected to your portable music player, smartphone, etc. The FiiO A1 allows you to adjust the volume and boost the bass in three levels. The LED display indicates the current battery status and the equalizer mode. The FiiO A1 is plug & play and requires no installation. With the FiiO A1, you can instantly amplify and improve the sound of your playback device. The battery lasts about 13 hours and can be charged using the included USB cable. A detachable transparent clip is included for attaching the FiiO A1 to clothing or a bag strap. The FiiO A1, housed in a high-quality aluminum casing, is robust, compact, and lightweight, making it ideal for on-the-go use.