Mens chain sizes usually starts at 18". If you have a thicker neck we'd suggest start with 20" for a choker look. 

Keep in mind that thicker chains (such as 19mm) fits tighter on the neck, so make sure to size up to achieve the look you need.

BRACELET SIZE GUIDE

1. Measure your wrist just below the wrist bone, where one would normally wear a bracelet, with a flexible measuring tape, or a strip of paper. 

2. If you are using a plain strip of paper, then measure that item with a ruler to determine your wrist size. 3. Add 1/4 inch to 1 inch to your wrist size, depending on whether you would like a snug, comfort, or loose fit.