These Flexible Navel Retainers are great if you want to avoid leaving the piercing empty and in danger of healing up. Size is 1.6mm gauge, 10mm length. The retainer has a small O-ring at the end to keep it in place. Watch you don't lose it! Also available are various Nose Retainers, Eyebrow Retainers, Labret Retainers and Tongue Retainers.