The hoop measures 19 mm (3/4 inch). 100% Hypo-allergenic. Gauge/Thickness: 1 mm (18 gauge). Pair of sterling silver Studex earrings which are ideal for everyday use especially if you have sensitive ears. Earrings feature a 18 GA traditional smooth hinged hoop. Hoops diameter measures 19mm (3/4"). Earrings are presented on a Studex padded card as shown and include butterfly backings to hold securely in place. The Sensitive range is an after-piercing fashion product, not to be used to pierce ears. Each classic style is made of the highest quality medical grade surgical steel and 24 K gold plated. The finest allergy-free earrings in the world. Studex Sensitive is the high fashion earring solution for people who suffer from nickel sensitivity. Each style is safe enough to be worn every day, guaranteed.