We do have lug nuts that fit 1/2 inch wheel bolts which are made from stainless steel, but the Chrome Trailer Wheel Lug Nut # 12CLN-L you asked about is made with a chrome plating.
I recommend checking out instead the Lionshead Trailer Wheel Lug Nut # LHLR103 which is made entirely from stainless steel. I have added a link to a video review of this lug nut for you to check out. view full answer...