Hexagon nut stud earring.
Stainless steel nuts soldered on a sterling silver post.
The earrings comes in 4 different sizes(Pic 5) :
Approx. 4mm width.
Approx. 5mm width.
Approx. 6mm width.
Approx. 7mm width.
If you need only a single, you can buy a mixed pair of any of the studs here:
Mixed Pair of G Studs
Unisex.