user-friendly competitive price small MOQ timely delivery Specificatins of Micro-ringMaterial: cooper, silicon, aluminumDiameter: 3mm, 3.5mm, 4mm, 4.5mm, ... our most valuable capital is the proficient workers with rich professional experiences. 3. Our factory possesses advanced techniques and equipment, high ... contact us. We will answer you within 24 hours. copper micro ring