This roller guide mounts to your window track and is what your regulator roller runs through. This one is 13 9/16 inches and will work on any 4 door model, sedan or wagon model.
This is the one for the FRONT door window. One per side. We also have a listing for pairs, if need be. Get those windows operating smoothly. 1955 1956 or 1957 Chevy. Made in the USA.