USB conversion connector set for au, FOMA, and Softbank, made of white plastic. - Type: Conversion connector - Compatibility: au, FOMA Softbank - Connectors: USB, Micro USB - Material: Plastic - Color: White Thank you for viewing. This is an old-type charging adapter or conversion cable used for au brand mobile phones. The part labeled "PRESS au" is likely a charger connector for a specific older mobile phone. The small connector at the bottom is the widely used Micro-USB type. These function as conversion adapters to enable charging and data transfer between different devices. au is a brand of KDDI Corporation, a major telecommunications carrier.