An earring post is a small metal rod that attaches to an earring and passes through the earlobe to secure the earring in place. The post is typically made from a durable metal such as gold, silver, or platinum and is attached to the back of the earring with a small screw or friction back.

Earring posts come in a variety of lengths, with the most common length being around 10mm. It's important to select an earring post that is long enough to comfortably pass through the earlobe while still leaving enough space for the earring to sit securely on the ear.

In addition to traditional earring posts, there are also other types of earring backs available, such as butterfly backs, bullet backs, and screw backs. These different types of backs can offer different levels of security and comfort depending on the individual wearer's preferences.

When purchasing earrings, it's important to consider the length and type of the earring post to ensure a comfortable and secure fit. It's also important to clean and maintain the earring posts to prevent infection and keep the earrings looking their best.