... ) HA (rubber sealed journal bearingaircooled bearing typeFormation or layer soft ,medium soft ,hard,medium hard,very hard formationButton size (extra features ... .3~346.17 3/8~13 5/8441~735120~50softClays, Soft Shale, Marl, Sands, Salts etc.295.2~174.63 ... /8-13 5/8490-78490-40Medium softShale, Marl, Sandstone, Soft Limestone etc.395.2~174.63 3/4-6 7 ... TCI Bit 165 mm with 3 1/2" REG Pin for Hard Rock