ACDelco Gold (Professional) Engine Timing Belt Tensioner Hydraulic Assemblies are a high quality alternative to Original Equipment (OE) parts. ACDelco Gold (Professional) parts are manufactured to meet your expectations for fit, form, and function, making them a smart choice for General Motors vehicles, as well as most makes and models, including special applications. These high-quality parts are backed by General Motors. Some ACDelco Gold parts may have formerly appeared as ACDelco Professional.