hey, I’ve done lots of reading about b16a O2 sensors on here, but never found exactly what i needed. The b16a has 2 O2’s on the exhaust manifold side by side, and they look identical but have different plugs. One green rectangular one and one circle one. I was wondering what the difference in the b18a and b16a O2’s. The price is different but they are both OBD0. I think i have seen OEM ones for the b16 for 220 a piece and that is insane. Thanks IA