IB-CB005 is a HDMI socket (female) to HDMI socket (female) coupler to extend the cable length without loss of the high transmission quality. It ensures optimal transmission of HD signals with the connection of two HDMI cables. You can easily plug this HDMI coupler between 2 HDMI cables. The HDMI socket is processed in milimeter precision so that your HDMI cables can fit it perfectly and thus the coupler will never slip. The HDMI port can provide up to 4K that is a resolution of 3840 x 2160. It's very common in newer and larger monitors or televisions. As a bonus, HDMI is able to transfer Audio.