ACDelco Professional, premium aftermarket Timing Belts are composed of high grade Hydrogenated Nitrile Butadiene Rubber (HNBR) for superior heat and contamination resistance and are equipped with premium high strength tensile members. They are GM OE equivalent or better in service life and performance and provide the most extensive coverage in the industry for import or domestic. These premium aftermarket replacement timing belts are manufactured to meet your expectations for fit, form, and function.