This is an XTUGA KP4 mixer. I purchased it last December and used it for about a month, so I think it's in relatively good condition. It's easy to use, and from a layman's perspective, there's nothing particularly concerning about its operation. I'm selling it because I'm updating my equipment. The following is a quote: [6-Channel Karaoke Audio Mixer] 6-channel Bluetooth mixer, built-in wireless Bluetooth, DSP reverb effect, 3-band equalizer adjustment, USB interface, and supports U-disk playback function. [Reverb & Delay Effects] The audio mixer has 16 built-in DSP effects. Hi-Res. Onboard 3-band EQ and gain control allow you to easily adjust the high, mid, and low frequencies of each channel. Suitable for computer music recording, live streaming, podcasting, small band shows, network anchors, conferences, weddings, etc. [USB Music Player & Bluetooth Wireless Connection] Directly insert a memory stick/MP3 into the USB port for immediate playback! With the USB mixer function, connect to smartphones, tablets, and PCs via Bluetooth (approximately 1.5 feet effective range) and mix music from multiple devices. Control playback/pause/track forward/mode switching freely with the mixer's Bluetooth operation. *USB mixer and Bluetooth cannot be used simultaneously. [Microphone Line & Audio Mixer Jack Input] In addition to the two XLR/6.35mm mono inputs (CH1-2), CH3-4 supports L/R 6.35mm + RCA stereo input. It can connect a wide range of devices, from dynamic/condenser microphones, wireless microphones, and instruments to CD players/keyboards/PCs, from professional equipment to consumer devices. The 6.35mm headphone jack makes it easy to check the volume in real-time.