This is the OS that is upstream or closest to the exhaust. The universal OS by Standard Inc. comes with 4 wires just like the original but you have to splice the wires to the old connector. The colors don't match on either side. The replacement has 2 white wires, 1 black, and 1 gray. The original has 2 black, one white and one green. Instructions don't indicate these color matches. I figure i need a wire schematic, but has anyone done this before that could tell me now before my car blows up?