This is a conversion cable that connects from a USB-A terminal to a 2.5mm 4-pole jack (DC2.5). It supports devices with a 2.5mm port, such as Bluetooth earphones, MP3 players, car audio systems, and mini speakers. This is a multi-functional type that can be used for charging, data transfer, and audio output. Length: Approximately 54cm Terminals: USB-A (male) ⇔ 2.5mm 4-pole plug (male) Uses: Charging / Data transfer / Audio support (※ Depending on the device) Compatible devices: MP3/MP4 players, Bluetooth headsets, car audio equipment, etc. Thank you for viewing.