This round ring is made of titanium steel which is rusty free and hard to deform,is a long lasting jewelry. This ring is temperature sensitive and will display differently according to the body temperature of the person. When you wear a ring on your finger for 20-30 seconds, it automatically displays the ceramic with temperature.The number that appears will change with the difference in body temperature. In other words, this is a ring that can measure real-time body temperature, or a portable thermometer. Each mood ring is made of durable stainless steel. The temperature display ring is highly resistant to oxidation, rust and corrosion. The inner arc of the ring is smooth, comfortable to wear, not sensitive, wear skin-friendly This is the ideal gift for Valentine's Day, birthdays, anniversaries, Christmas, Thanksgiving, etc., to express your best wishes and a perfect replacement for wedding rings. Features Material: Titanium Steel. Color: Golden, Silver, Black. Surface Width: 8mm