... 17 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 ... lock the conewhich reduces the probability of cone-dropping to minimum.Main Type AvailableSize: 8 1/2",9 ... the cone which reduces the probability of cone Cdropping to minimum.Main Type AvailableSize: 2 3/8",3 ...