7pcs Glow In The Dark Belly Button Navel Bar Rings Body Piercing Jewelry (Random Colors) Condition: New without tags Ball Material: Plastic. Bar Material: Surgical Steel Total Length: About 23mm. Bar Length:10mm. Bar Diameter: 1.5mm. Ball Diameter: 5mm/ 8mm Size: as show in the picture 7 bright colors, randomly sent. Notice: You need to put them under the sunshine to absorb enough light for them glow in the dark.