Each lot contains 4 Niobium earwires (2 pairs). These earwires are a Dark Copper color With a bright copper 3mm ball. Measurements: from hook to bottom of loop is 14.8mm, 8mm deep. Loop is open and has an interior diameter of 2.8mm. Wire is 20 gauge. Niobium is a rare precious metal, highly desirable for jewelry because it is physiologically inert, thus hypo-allergenic. Please note: The definition of hypo-allergenic is "having a decreased tendency to provoke an allergic reaction". This does not mean that a wearer is guaranteed no allergic reaction. Some people are allergic to pure gold, just as many suffer from Nickel allergies. We provide this as a low-cost alternative to precious metal, and we verify that it is Nickel, Lead, and Latex free, thus it is less likely to cause an allergic reaction.