OE Number of Serpentine Tensioner: 12554027, 12580162, 88929140Fitment of Automatic Belt Drive Tensioner: for Chevrolet Express 1500 2500 2003-2008 for Chevrolet Silvera 2001-2006 for Chevrolet Silverado 1500 1999-2008 for Chevy Avalanche 1500 2002-2008 for Chevy Avalanche 2007-2008 for Chevy Trailblazer 2006-2009 for GMC Envoy 2001-2006 for GMC Savana 1500/2500/3500 2003-2008 for GMC Sierra 1500 1999-2008 for Hummer H2 2003-2008 for Isuzu Ascender 2003-2006 for Saab 9-7x 2005-2009 for Buick Rainier 2004-2007 for Cadillac Escalade ESV 2002-2008 for Cadillac Escalade/ Escalade 2002-2008 Specification of Belt Tensioner and Pulley Assembly: Color: Silver Tone, Black Material: Metal Total Size: 17x10cm / 6.69" x3.94"(L*W) Hole Diameter: 12mm / 0.47", 13mm / 0.51" Include 1 x Accessory Drive Belt Tensioner Assembly. Feature of Belt Tensioner w/Pulley: Replace the old or broken belt tensioner to avoid noisy tensioner pulleys and no longer withstand belt noise. Achieve proper belt tension, and alignment, and ensure the good performance. Torsional round spring provides reliability and consistent tension Take the tension off and pull the pin out after getting the belt in position. The tension force is automatically adjusted to make the transmission system stable due to the different tightness of the belt. Solid metal for wear resistance, not easy to break or deform, ensures longer service life. Please allow slight dimension differences due to different manual measurements. This is a non-OEM product, accessory only!