This is the "ProDX4," an ultra-compact 4-channel digital mixer from the prestigious audio equipment manufacturer MACKIE. Its most notable feature is the wireless control function via Bluetooth connection. You can intuitively control volume, EQ, 16 built-in effects, and more using the dedicated "MixerConnect" app on your smartphone or tablet. The unit features hardware controls on the front for quick adjustments with a single knob, and an integrated bridge (groove) on the top to hold your smartphone, making it a highly functional mixer despite its compact size. [Product Condition] Regarding Operation: Basic input/output and operational checks have been completed for this listing. It is ready for immediate use. Regarding Appearance: A sticker reading "ONKYO TOKKI LTD. INSPECTED" is attached to the back, indicating it is a unit that has undergone official distribution and inspection, providing peace of mind. There are minor scuffs associated with normal use, but no noticeable major scratches or dirt. It has been carefully stored. The genuine AC adapter (with MACKIE ProDX4 label) is included as an accessory. [Recommended Points] This mixer is ideal for solo live performances, small-scale events, podcasts, and live streaming for individuals who don't want to increase their equipment but don't want to compromise on sound quality or features. The convenience of being able to remotely fine-tune the sound from the audience's perspective with just one smartphone is something you won't want to give up once you've experienced it. Its compact size won't clutter your desk, and we confidently recommend it to anyone looking to build a professional PA system.