6x2 Matrix for HDMI 4K x 2K - black, 2x Audio Out - TOS-Link. The Gefen GTB-HD4K2K-642-BLK ToolBox 6×2 Matrix for HDMI is a compact and lightweight alternative to rack-mounted matrixes. It allows up to six Ultra High Definition 4K or 1080p Full HD sources to be routed to up to two Ultra HD displays. Each Hi-Def source can be routed to either of the connected displays using the front panel push-button controls, the included IR remote, RS-232 serial control interface, or through IP, using Telnet, UDP, and the built-in web server interface. LED indicators on the top panel display the current routing status, FST mode, audio configuration, and EDID settings.