PLEASE SELECT YOUR COLOR AND SIZE AT BEFORE ADDING TO CART. . Size Reference19mm = 9 (US)20mm = 10.25 (US) Please measure your finger size before buyingMaterial: Titanium steel (High quality material does not fade)Package Content :1x Ring1x Ring Box This self-defense ring is like a classic ring but with a hidden blade. It can be used for style and a good self-defense tool at the same time. The knife ring is made of sturdy S3 Titanium steel with precision craftsmanship, strong and durable, more sturdy and durable than traditional rings and it is not easy to damage. This ring knife is perfect for Valentine&';s Day, Mother&';s Day, Father&';s Day, Anniversary, Thanksgiving and other special occasions to surprise your girlfriend, loved ones, colleagues, lovers and family members. If you have any questions about our products, you can contact us at any time, we will reply within 24 hours.