... improve the reliability and durability of bearing seal.Main Type Available Size: 6",6 1/2",7 1/2 ... opener bit ,reamer bitadvantagemost favourable price and best qualtitybearing type:sealed bearing and non-sealed bearingHJ(metal sealed journal ... to 7 daysMarketCanada, USA,Middle east ,Africa,EuropeApplicationpetroleum&gas ,water well ,mining and tectonic industries ,oil field, construction, geothermal, ...