Pulley Belt Width (mm). Shaft Overall Length (mm). Piston Outside Diameter (in). Number of Mounting Holes. ETB Inside Diameter (in). S13-124, S13-94, S13-94A, 20513065. Customer Service Available 7 Days A Week. WE STRIVE TO PROVIDE A 5 STAR EXPERIENCE! With the exemption of U. OEG Parts is not responsible for carrier delays such as weather or natural disasters. We always recommend cross referencing a part number to ensure fitment as well.