... 1/2" tricone drill bit : size from 60mm to 26 inch,metal sealed and Elastomer sealed,have new and old in stock.export to ... many countries,have a good feedback. 1. Metal-face sealed bearing ... the probability of cone-dropping to minimum.Main Type AvailableSize: 8 1/2",9 1/2",9 5/8",9 7/ ... Cdropping to minimum.Main Type AvailableSize: 2 3/8",3",3 5/8:",3 7/8",4",4 1/2",4 ...