Inner diameter is approximately 16mm, which I believe is about a size 10. The box is not included as it was used for photography. I only tried it on, but I'm selling it to declutter. I believe it's a 925 stamped silver product. The beautiful large center stone is approximately 15mm x 10mm. It has a dazzling presence due to its size, but the simple design gives it a calm and elegant impression. The delicate decorations on the shoulders also sparkle beautifully, making it a lovely and cute design. Available for immediate purchase. Same-day shipping available.