If your 57 Chevrolet has the long Bel Air style arm rest, new or old, this will get the job done. 
This is a set of 12 screws to do TWO armrests and brackets. There are 4 in each bracket and 2 in each armrest. These are for the long Bel Air style armrest in a 57 Chevy. The bracket is NOT included; it is there for display purposes. These are the correct diameter and thread pitch as the original. 
To accommodate your needs, we have other listings with qty's to allow for you to do just one or four armrests. Again, this listing will complete two armrest assemblies, perfect for two door cars.