From the seller:

675R/T is a high-performance HDMI fiber extender kit for ultra-reach extension of 4K at 60Hz (4:4:4) HDMI signals. 675T converts the HDMI input signal to an optical signal that is transmitted over a fiber optic cable to 675R, which converts it back to an HDMI signal. 675R/T includes 2 multi-mode SFP+ transceivers, but can be used with any Kramer certified SFP+ transceiver, such as a single-mode SFP+ transceiver. Features: High Performance Standard Fiber Extender Kit - Provides ultra-reach signals over either multi-mode or single-mode optical fiber infrastructures, using Kramer pluggable OSP SFP+ units. Near-zero latency video chroma sub-sampling conversion technology, is employed to auto-adapt above 10G HDMI signals to 10G optical link signal data-rate. Note: To ensure specified performance, support, and warranty of this product, use only Kramer"s certified hi-performance OSP SFP+ pluggable optical units. HDMI Signal Extension - HDCP 2.2 compliant and supports up to 18G (6G per channel) data rate, LPCM 7.1, Dolby True HD, and DTS-HD as specified in HDMI 2.0. I-EDIDPro™ Kramer Intelligent EDID Processing™ - Intelligent EDID handling, processing and pass-through algorithm that ensures Plug and Play operation for HDMI source and display systems. Cost-Effective Maintenance - Status LED indicators for power, source, sink, and fiber link connections detection facilitate easy local troubleshooting. Easy Installation - DigiTOOLS® rack mountable fan-less enclosure enables side-by-side mounting of 3 units in a 1U rack space with the recommended rack adapter.