What is a flat gold necklace called?

Curb chains are a very popular choice, particularly with men as they are available with heavy, large links. The curb is a simple and classic design of flat, interlocking, identical links.

What are flat necklaces called?

A flat chain made from a double cable that has been “swaged” or drawn through a flat condensing die. The resulting chain is smooth and solid in appearance with a mirror surface. Herringbones are not flexible and can easily kink

The advantages of flat gold necklace

Extra durable. All the connecting parts are soldered one by one with attention to detail.
Smooth and solid in appearance with a mirror surface.