Spiral Twist Barbell Ring,HELIX OPAL crystal inset stone, 16 gauge, orbital, piercing, eyebrow barbell piercing, hoop crystal inset Unusual & striking "Twister Ring" with sliding inset Opalescent colored crystal 16 gauge wire, 8mm wide, about 2mm inset "STONE" Stone slides out to insert wire, then slide back in and "click" to hold in place Popular in brow, barbell, helix, orbital, and similar cartilage piercings Opal crystal often used for April, June, or October birthstone