Automotive-leader 2pcs 234-4390 234-4396 O2 Oxygen Sensor 1 Sensor 2 Upstream Downstream for 2004-2005 Mazda 3 2.0L-L4 Canada and Exc Calif. 2004-2005 Mazda 3 2.3L-L4 2006-2007 Mazda 5 2.3L-L4

First review got removed. There is only 1 o2 sensor in the box, the upstream. Although the description says it’s a 2 piece, with both the upstream and downstream, the box from was for just the upstream.

Buen repuesto