I found these in my father-in-law's wood shop when he passed away. They are a set of chrome (or stainless) wheel cover rings that fit under a center cap. They are for sale, make an offer. 47Plym had pictures of trim rings from his '47 Plymouth and these look identical. The combination covers the whole wheel. The outer diameter is 15 and a quarter inches and the inner hole is 9 and a quarter. The back has four sets of metal clamping tabs and is plated in a brownish color, possibly anodizing. They were in his dry, heated basement woodshop for decades. They cleaned up decently and the plating is aged but has good shine. There are little dings and scratches, two of the rings have curb dents but not serious. Just a little surface corrosion on the back sides.
lots of cars had those in the 50's, they made your small hubcaps look like a full wheel cover. they were available both aftermarket and from the factory. no way to tell what they went to without trying them on a rim and hubcap