These are extra extension interface cables for your Diagnostic OBDI & OBDII reader/scanner.
They are specifically for Specifically for trucks, trailers, buses and other heavy commercial vehicles — that use a proprietary OBD port (and that won't fit with your scan tools plug).
One end goes into vehicles OBD port. Other end connects to diagnostic readers/scanners 16-pin port.
8 cables in total, that include...