APPLICABLE MODELS - Air Fuel Ratio Sensor Compatible with Forester 2014 2015 2016 2017 2.0L L4. FIT VEHICLES - O2 Oxygen Sensor Compatible with WRX 2015 2016 2017 2.0L L4. FUNCTION - DOSKJOK Oxygen Sensors are manufactured under rigorous scientific standards and 100% tested out of the factory.It is more durable, oxidation resistant and high temperature, to ensure long-term stable performance, improve vehicle fuel economy, help engine smooth operation, reduce exhaust emissions and enhance environmental protection. INSTALL - Oxygen Sensors directly replace the old parts in the original position of the installation without change,easy to install on your vehicle, and come with pre-coated threads to assist installation. NOTES - Please carefully check your vehicle year & make & model，pictures and parts No to confirm the compatibility before purchasing. Please let us know if you have any questions. ✔️CAUTIONS ✔️Pls carefully verify your year & make & model in the product details or check your parts pictures, parts No with ours before purchasing so as to prevent wrong purchasement and unnecessary expenses. ✔️If you find the parts not fit your car when you received, pls kindly send it back with undamaged package. Thank you! ✔️Please let us know if you have any questions，we will reply you in 24 hours and offer the solve way for you.