Sterling silver Adjustable Only worn once! From website: “Care Instructions- Our jewelry was created with the utmost love and care. Follow these guidelines to help keep your jewelry looking its best year after year. Use the ALEX + ANI polishing cloth to effectively clean your jewelry – great to use on Trend metals, Stainless Steel, and Precious metals. If your jewelry requires further cleaning, use mild soap, water and a soft cloth. Rinse with clean water and pat dry. Use the soft toothbrush to clean crystals if necessary. Make sure your jewelry is completely dry before storing. Eco friendly Safe materials”