The most common gauge for a helix piercing is 16 gauge, although some are done at 14 gauge instead. If you had your ear pierced with a gun, the gauge you wear may be smaller than the standard size, such as 18 or 20 gauge. The hoop diameter you need depends on your individual anatomy, piercing placement, and personal preference. The recommended inner diameter for hoops for piercings closer to the edge of the ear is 5mm - 7mm. The bar length for labret/barbell is usually 6mm or 8mm, depending on your skin thickness and piercing location. If you have thicker cartilage or prefer to leave a bit of space, a 6mm length is recommended for a short and snug fit. To determine your gauge size, you can insert a standard earring post through your piercing. If it fits snugly, then your gauge size will be 20G.