Base Material: 925 Sterling Silver Depth: 10mm (Approximately) For: Men / Nurse Stone Color: Black Ring Size: US 4 - US 16 (Default is US 7) Thickness: 1.5mm Handling Time: 7 - 10 working days It comes with a classic jewelry box. When you're not wearing your sterling silver jewelry, be sure to keep it in a ziplock or airtight baggie as this will prevent moisture from oxidizing it. You can use a silver polishing cloth to remove oxidation from silver and cleaning it right away will make it easier to restore the shine.