This is a custom harness built for an M4 in a B, D or H series engine configuration. It plugs into a MoTeC M4 ECU and all the factory honda sensors. Some minor wiring is included depending on what sensors and options you want to use on the MoTeC. This is the same harness we run in our record setting SFWD car. The harness is assembled using mil spec tefzel wire and DR25 heat shrink. MoTeC M4 not included.