... . 2.The advanced metal seal package will improve the reliability and durability of bearing seal.Main Type Available Size: 6",6 1/2",7 1/2",8 1/2 ... ",9 1/2",9 5/8",9 7/8",12 1/4",17 1/2", etc. IADC Code:4 ... performance.Main Type AvailableSize: 5 7/8",6",6 1/2",7 1/2",7 7/8",8 1/2",9 1/2",9 5/8",9 7/8",12 ...