These are "Shining Adjusters," featuring Swarovski crystals decorating the top of L-shaped adjuster screws. The crystals are SWAROVSKI Tanzanite Shimmer (dark blue). This is a Shimmer effect that appeared in Swarovski in 2018. "Shimmer" means sparkle, and the effect is a "polarized effect with a thinness that allows the base color to be seen through." It's similar to the Aurora (AB) effect, but it has a transparency that more clearly reflects the color of the base glass. The surface is coated with a polarized coating, giving a glamorous impression. The screws can be replaced with the L-shaped adjuster screws currently used on violins and violas (Wittner, Stradpet, etc.). Screw diameter: JIS M2 Made of steel (gold-plated), with a pointed tip. Crystal: Swarovski Flat Back Tanzanite Shimmer ss20 This product is a screw-attached adjuster. Tailpiece and instrument are not included. When replacing the adjuster screws, it is recommended to protect the instrument with a cloth or similar to prevent scratches. May your violin's sound resonate like the shining light of the crystals.