This is a .925 sterling silver skull with horns belly button ring fabricated with a 316L high grade surgical steel shaft. The unique skull has jewels in the eyes in your choice of clear, light blue, dark blue, green, purple red, or pink. The externally threaded top ball size is 5mm. This navel ring measures 14 gauge and 10mm- 3/8 of an inch. Entire piece is nickel free.