OEM FACTORY OXYGEN SENSOR. Mazda PART NUMBER FS1G-18-861A 9U. PLEASE CHECK THE PART NUMBER CAREFULLY TO BE SURE THIS IS THE CORRECT ITEM FOR YOUR VEHICLE.

As you can see from the compatibilities, this is for Mazda 626 with a 2.0 liter engine, but it is possible that it fits other models also.

Brand new in the original Mazda box. This is not an aftermarket, cheaply made sensor. These sell for well over $165 on the Madza OEM website.