Purchased new for around 2900 yen and used for testing, but haven't used it since, so I'm selling it. I've disposed of the outer box, so there are some minor scratches from handling, but there are no issues with its use. The instruction manual has some stains from the tape's adhesive, but you can read the text without any problems. I've re-confirmed that both sending and receiving work. I didn't notice any audio delay, at least to my untrained ear. The following is quoted from the purchase site: Transmission Mode (TX) Turns video equipment like TVs and computers, and audio equipment without Bluetooth, wireless, allowing you to enjoy them with Bluetooth speakers, earphones, and headphones. Reception Mode (RX) When you want to wirelessly connect wired earphones or speakers, use the reception mode to make them wireless and enjoy music from Bluetooth-enabled smartphones and laptops. Latest Bluetooth 5.0 This product is equipped with the latest Bluetooth 5.0, which strengthens the signal, doubles the data transfer speed, and increases broadcast communication capacity by 8 times (compared to Bluetooth 4.2). 12 hours of use A large-capacity battery is built-in, allowing for approximately 12 hours of continuous use. After about 5 minutes of inactivity, it automatically enters power-saving mode, and the LED indicator light turns off. High-quality sound, low latency Supports aptX HD and AAC, allowing you to listen to music wirelessly with higher sound quality. There is less sound quality degradation and high-frequency attenuation during data transfer, allowing you to enjoy high-quality, natural sound. Type: Bluetooth receiver/audio adapter