Application Compatible for Nissan Frontier 1999 V6 3.3L VG33E Upstream & Downstream- Frontier 2000 V6 3.3L VG33E Upstream & Downstream Automatic Transmission Frontier 2003 V6 3.3L VG33E Upstream & Downstream SOHC Xterra 2000-2003 V6 3.3L VG33E Upstream & Downstream Specification Wires: 4 Position: Upstream & Downstream Reference OEM :250-23109, 234-4700, 234-4703 Package Include: 4 Pcs Oxygen Sensors (Upstream & Downstream) as Pictured Note- Please check OE with listed pictures above & make sure it fits you vehicle. - No instruction included; Professional installation & alignment suggested. - Please check our store for other auto parts you may be interested in. - Please feel free to contact us for whatever we can help.