This is a 9 pin full size JST connector harness, (male). It uses a
TCS 1374 female socket with NMRA coded wires soldered to it. It is like TCS #1345 but $16+ cheaper.
It is intended as an interconnect harness between engines or between a steam engine and tender. It mates with a standard decoder harness (not included) to make up a complete interconnect harness.
We use these in HO, S, O, and G scale installs.