The Double 4 Prong Round Gem Hybrid Curved Barbell has a 4 Prong Setting made out of 14k Gold and the Curved Barbell is made out of Surgical Steel. The Bottom Round Gem is 6mm in size and is permanently attached to the Curved Barbell. The Top Gem is a 3mm Round Gem and the setting is also made out of 14k Gold. These two metals fuse well together for a very solid piece. This piece is internally threaded for your comfort and can be made in either White or Yellow Gold with your choice of gem colors.