Ultra High-Speed HDMI cables are a new cable type released for the HDMI 2.1 specification, and they are category 3 cables. Initially called 48G cables, an Ultra High-Speed HDMI cable supports data rates up to 48 Gbps. The increased speed is required to support the new features of HDMI 2.1 – uncompressed 8K/60p, 4K/120p and high-resolution audio via eARC. It is fully backward-compatible with older HDMI connections.