... drilling rate and added cutting structure durability in medium-to-medium hard formations.3)The HSN rubber O-ring provides adequate sealing ... 5/8",9 7/8",12 1/4",14 3/4",17 1/2", etc. IADC Code:4-- Series, 5-- Series, 6-- Series,etc ... of cone Cdropping to minimum.Main Type AvailableSize: 2 3/8",3",3 5/8:",3 7/8",4",4 1/2",4 5/8",4 3/4",6",6 1 ...