Sterling silver chain.
Please note that Sasha Hoop Earring post might bend while wear, as it's made of sterling silver. You can easily straighten it again and it doesn't break easy.
Avoid contact with any liquid, humidity, heat, and overexposure to the sun. Store in an airtight bag to prevent a tarnish/discoloration. Wipe with a dry cloth if needed. To remove tarnish, use a silver polishing liquid or cloth.