3Pcs 3Styles:You will receive 3pcs blank ring bases divided into 3 styles the initial inner diameter of the ring is 17.5-18mm/0.69-0.71 inch. Brass Material:These ring bases are made of brass which is strong and durable does not easily break or and is lightweight and comfortable to wear for long-term use. Adjustable Finger Ring:The inner diameter of the ring fits adult sizes and can be easily adjusted to fit different finger sizes so you don't need to stock up on multiple sizes of rings. Easy to Use:Simply pick the right cabochon and glue it to the empty ring tray. Perfect for making your own beautiful rings. Wide Application:You can glue cute patterns or various decorations such as small candies shells logos resin dried flower petals pearls crystals cameos gemstones small beads and so on to make your ring trays more beautiful. Great DIY accessory for home and amateur jewellery making.