< GO BACK Gefen Announces HDBaseT Signal Extenders Transmitting 4K, 1080p Posted on 2014-12-19·By Robert Archer Gefen ToolBox 4K Ultra HD ELR-POL Extender with RS-232 and IR (SKU: GTB-UHD2IRS-ELRPOL-BLK). Posted in: HDBaseT, HDMI, Networks Tagged with: 4K, Gefen