Meet the Threaded Collection. Crafted in recycled 14 karat yellow solid gold, this stud has an internally threaded post and flat back. The collection was developed in close collaboration with a piercing expert to ensure it conforms to international guidelines, using antibacterial, nickel-free & hypoallergenic materials. We have partnered with RUUBY, the UK's premium beauty concierge, who will be exclusively offering Otiumberg's solid gold Threaded Stud Collection for at-home piercing .