The helix piercing is a perforation of the helix or upper ear (cartilage) for the purpose of inserting and wearing a piece of jewelry. The piercing itself is usually made with a small gauge hollow piercing needle, and typical jewelry would be a small diameter captive bead ring, or a stud.
Sometimes, two helix piercings hold the same piece of jewelry, usually a barbell, which is called an industrial piercing.
The information that helix piercings do not have nerve endings and do not hurt is completely false. They do hurt like any other cartilage piercing, and, when you bump or tug on them by accident during healing it can be extremely painful. However, when they are just sitting there not being irritated or touched, they do not hurt at all. Just be careful of bumping them during healing, which can take up to 1 year.