These are brand new Denso oxygen sensors. This is the correct upstream sensor for LS harnesses that use the flat 4 pin connector.
Denso, Exhaust, Oxygen Sensors (O2)
Denso LSx Oxygen sensor / O2 sensor (flat 4 pin connector) #234-4012
$31.99
SKU: 234-4012
Categories: Denso, Exhaust, Oxygen Sensors (O2)