... hard, medium hard, very hard formationBearing typeSealed bearing and non-sealed bearingHJ(metal sealed journal bearing)HA( ... rubber sealed journal bearing)Aircooled bearing typeapplicationPetroleum and gas, water well, mining and tectonic industries, oil field, construction, ... inserts with customized angles, diamond thickness, chamfers, and sizes.Hejian Wanda Petroleum Machinery Co.,Ltd. Supplies ...