This Dorman window regulator and motor assembly is designed for Kenworth and Peterbilt trucks, specifically for the front right side window. It is a direct replacement part with an interchange part number of R21-6013R. The window mechanism part is a window motor/winder part. This product is made by Dorman, a well-known brand in the automotive industry. The California Prop 65 Warning applies to this product, which can expose users to chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. No returns for fitment