A wheel nut or lug nut comes in fine thread, low carbon steel with either right- or left-hand threads. They are available in both standard and metric threads. They are not locking nuts, though they do look very similar to a Stover-style lock nut. They are typically zinc plated to provide some corrosion resistance.

The best way to determine if a thread is right-hand is to try a standard bolt of the correct size in the nut to see if it threads. This way you can determine both the size and thread pitch of the nut. If it's left handed, it'll be very hard to find a bolt to fit as left-hand bolts are not standard. (But we can get those, too, if you need them.)