This is a set of 4 specific fit upstream and downstream O2 oxygen sensors designed for 2004-2006 Nissan Altima and Maxima 3.5L models. The sensors have a metal housing and feature a blade terminal type with a thread size of M18*1.5. They are a direct replacement with a custom bundle including 5 wires for each sensor. The sensors are heated and come with a 1-year manufacturer warranty. The manufacturer part number is ADP83622800S, and they have various OE/OEM part numbers such as OS5393, ES20172, and 234-5060.