... From 2 7/8 to 26”larger sizes for hole opener bit ,reamer bitadvantagemost favourable price and ... hard,medium hard,very hard formationButton size (extra features)Button bit,saw teeth1) Y-Conical teeth 2) X ... hole opener,hole enlarger,drag bit,button bit and drilling equipment for petroleum&gas ,water well ,mining ... .63 3/4-6 7/8294-53980-40Contact information TCI Bit 165 mm with 3 1/2" REG Pin for Hard ...