The post length determines how much of the post extends through your piercing. Standard Length - 9mm post: Most common length, especially for younger lobes. Long Length - 11mm post: Provides an additional 2mm of length, giving you more room for thicker earlobes (typically more common on adults) or temporary swelling. Earring Dimensions: * Post Size: 20 gauge, .8mm * Earring size: 4mm W x 4mm H