Please read descriptions for metal and size information & Jewelry Care.
Surgical Steel is the most common type of metal used with body jewelry and it is durable, safe and will not tarnish with proper care. This does contain some nickel so it is not a good choice for those with sensitive skin.
Titanium is the go to for those with sensitive skin because it does not contain any nickel.
Copper can tarnish when reacted with chemicals and/or after long term use. This is not a good option for those with sensitive skin.
If you have sensitive skin, please be cautious when purchasing & ensure you are checking with a piercer to discuss which metals are okay for you.
Also, please make sure you are self cleansing your body jewelry, initiating proper care & doing your own research on metals & gauge sizes.