Hi Venita, I'm glad to assist you. That refers to the location only. It is similar to the upstream and front oxygen sensor. The other location is rear, or after, also called downstream. Please tell us if your mechanic advised you to buy the front and rear sensors. Also, for us to carefully check and be accurate on the part that you need, please provide the complete information of your vehicle (year, make, model, submodel, and engine size). I hope this helps. Happy shopping. https://www.carparts.com/oxygen-sensor/drivewire/set-arbl960907-2?can=CPJE1043_20220611

The “Before” oxygen sensor screws into the exhaust pipe in front of the catalytic converter. “After” would screw into the exhaust pipe leaving the catalytic converter towards the back of the car. There are special sockets that you can buy that allow the unplugged oxygen sensor wires to turn in tandem with the sensor without destroying them. You can also buy a 7/8 inch or 22 mm socket and grind an opening to allow for the unplugged wires.

Hi Travis, thank you for reaching out. Yes, that is correct. You can use this link to continue ordering the part at a discounted price today: https://www.carparts.com/oxygen-sensor/drivewire/set-arbl960907-2?can=CPAP3648_CSQA_20230607 I hope this helps. Enjoy shopping.