1.A: 4K 30Hz/4K60Hz 4x4 HDMI matrix with audio, featuring 4 output ports capable of displaying definition video from the same or different signal sources. 2.B: Switch mode for flexible viewing: fourway output with independent displays, offering diverse multichannel signal options to select different sources for output. 3.C: Multiple switching methods: innovative design with dual remote controls buttons. 4.D: 3.5mm Digital Optical Audio Output: The matrix includes a 3.5mm digital optical audio interface, compatible with external audio devices such as speakers, headphones, amplifiers, and mixers. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Dadangjia