... design, combined with maximum cone offset, results in high bit penetration rates.4)The deep intermesh ... of cutter rows prevents bit balling in sticky formations .TCI Tricone Bits 535 Medium Formation ... rate and added cutting structure durability in medium-to-medium hard formations.3)The HSN rubber O-ring ... 2 3/8",3",3 5/8:",3 7/8",4",4 1/2",4 5/8",4 3/4",6",6 1/2",7 1/2",8 1/2",9 1/2", ...